The smallest in the Ronstan Ball Bearing Block line (replacing the discontinued Series 19 Blocks), the new Ronstan Series 20 Blocks have a number of --Smart Features-- and improvements with very high maximum working loads between 440 and 880 lbs depending on the block configuration.  Sheaves are 20mm (3/4 inch) and support a max line size of 1/4 inch (6mm).  High-load (HL) blocks can handle wire to 1/8 inch in diameter. Use these blocks for almost all control line situations on small dinghies. Work well for lightly loaded control lines on larger boats as well.  Can be used for outhauls, vangs, barberhaulers, cunninghams, traveler controls, leach cords, lead car return tackles, and even flag halyards. 

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways. The cheek block sits flat on deck and is mounted with a bolt directly through the hub of the sheave for high strength.

The second smallest in the Ronstan Ball Bearing Block line (replacing the discontinued Series 28 Blocks), the new Ronstan Series 30 Blocks have a number of --Smart Features-- and improvements with very high maximum working loads between 550 and 1100 lbs depending on the block configuration.  Sheaves are 30mm (1-3/16 inch) and support a max line size of 5/16 inch (8mm).  High-load (HL) blocks can handle wire to 5/32 inch in diameter. The pin diameter on these blocks is 3/16 inch. Use these blocks for almost all control line situations on small dinghies. Work well for lightly loaded control lines on larger boats as well.  Can be used for outhauls, vangs, barberhaulers, cunninghams, traveler controls, furling line leads, and even flag halyards. 

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways. The cheek block sits flat on deck and is mounted with a bolt directly through the hub of the sheave for high strength.

Third in the Ronstan Ball Bearing Block line, the Series 40 Blocks incorporate  --Smart Features--  with maximum working loads between 770 and 1320 lbs depending on the block configuration.  Sheaves are 40mm (1-1/2 inch) precision molded U.V. stabilized Acetal  with Acetal ball bearings and support a max line size of 3/8 inch (10mm).  High-load (HL) blocks can handle wire to 5/32 inch in diameter and have extruded Nylatron sheaves. The pin diameter on these blocks is 3/16 inch. Use these blocks for vangs, backstays, cunninghams, traveler controls, furling line leads and main/jib/spinnaker sheets. Work well for mainsheet, jib sheet, and control line situations on boats up to 26 feet. Ronstan Series 40 Blocks are incredibly strong for their size.  

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways. The cheek block sits flat on deck and is mounted with a bolt directly through the hub of the sheave for high strength.

Third in the Ronstan Ball Bearing Block line, the Series 40 Blocks incorporate --Smart Features-- with maximum working loads between 770 and 1540 lbs depending on the block configuration. Sheaves are 40mm (1-1/2 inch) precision molded U.V. stabilized Acetal and support a max line size of 3/8 inch (10mm) [except for RF40130 with max line size of 5/16" (8mm)]. The All Purpose (AP) blocks in the 40 Series do not have ball bearings but are extremely durable requiring virtually no maintenance. The pin diameter on these blocks is 3/16 inch. Use these blocks for vangs, backstays, cunninghams, traveler controls, furling line leads and main/jib/spinnaker sheets. Work well for mainsheet, jib sheet, and control line situations on boats up to 26 feet. Ronstan Series 40 Blocks are incredibly strong for their size.

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways. The cheek block sits flat on deck and is mounted with a bolt directly through the hub of the sheave for high strength.

Ronstan Series 40 Fiddle blocks, like the rest of the 40 Series incorporate the Rontan  --Smart Features-- . These fiddles have maximum working loads between 770 and 880 lbs depending on the block configuration.  Sheaves are 40mm (1-1/2 inch) precision molded U.V. stabilized Acetal and support a max line size of 3/8 inch (10mm).  The RF40_ Ball Bearing (BB) fiddles have Acetal ball bearings.  The RF41_ All Purpose (AP) fiddles do not have ball bearings but are extremely durable requiring virtually no maintenance.  The pin diameter on these blocks is 3/16 inch. Use these blocks for purchase mainsheet and boom vang systems, and control line purchase systems on larger boats, including fine tune tackles, outhauls, checkstays, cunninghams, genoa lead pullers, and traveler controls.  

Like with the other Ronstan blocks, Series 50 Blocks incorporate  --Smart Features--  with maximum working loads between 1100 and 5290 lbs depending on the block configuration.  Sheaves are 50mm (2 inch) precision molded U.V. stabilized Acetal  with Acetal ball bearings and support a max line size of 1/2 inch (12mm).  High-load (HL) blocks can handle wire to 3/16 inch in diameter and have extruded Nylatron sheaves. The pin diameter on the single blocks is 3/16 inch and on doubles/triples 1/4 inch. Use these blocks for mainsheet, halyard, vang and spinnaker control applications on one design keelboats and sportboats to 33 feet. Also ideal for many control lines on larger boats.

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways.

Like with the other Ronstan blocks, Series 50 Blocks incorporate   --Smart Features--  with maximum working loads between 1100 and 2640 lbs depending on the block configuration.  Sheaves are 50mm (2 inch) precision molded U.V. stabilized Acetal and support a max line size of 1/2 inch (12mm).  The All Purpose (AP) blocks in the 50 Series do not have ball bearings but are extremely durable requiring virtually no maintenance.  The pin diameter on the single blocks is 3/16 inch and 1/4 on doubles/triples. Use these blocks for mainsheet, halyard, vang and spinnaker control applications on one design keelboats and sportboats to 33 feet. Also ideal for many control lines on larger boats.  Ronstan Series 50 blocks are 10-15 percent more compact than other blocks in their class that do not even come close to matching their strength.

Smart Features available on the configurations in this series consist of captive lock, swivel, loop, and shackle heads, ringless keyhole becket pins, quick adjusting cleat angles, and rinsing cutouts. Double and triple blocks are supplied with a shackle and have formed loop heads which can be attached directly to a line or attached to a shackle in three different ways. 

Ronstan Series 50 Fiddle blocks, like the rest of the 50 Series incorporate the Ronstan  --Smart Features-- . These fiddles have maximum working loads between 1100 and 1650 lbs depending on the block configuration.  The large/small  sheaves are 54mm/34mm (2-1/8 inch/1-5/16 inch) precision molded U.V. stabilized Acetal and support a max line size of 3/8 inch (10mm).  The RF50xxx Ball Bearing (BB) fiddles have Acetal ball bearings.  The RF51xxx All Purpose (AP) fiddles do not have ball bearings but are extremely durable requiring virtually no maintenance.  The pin diameter on these blocks is 3/16 inch. Use these blocks for purchase mainsheet and boom vang systems, and control line purchase systems on larger boats, including fine tune tackles, outhauls, checkstays, cunninghams, genoa lead pullers, and traveler controls.  

Low friction 2-stage ball bearing system provides consistent performance over the full load range. Hight static and dynamic load capacity. Light weight. Head posts of swivel blocks can be locked at 0 or 90 degrees. Cheek cut-outs for easy bearing maintenance. Removable becket pins allow lines to be spliced prior to fitting. Blocks can be dissasembled for servising or customisation. Max line diameter is 10mm (3/8"). Pin diameter on the post is 6mm (1/4") except for light load block, which is 5mm (3/16").

Great for: mainsheet and spinnaker sheets on sportsboats to 33', halyard, vang and backstay applications on boats to 30', and various control line applications on larger yachts.

Pivoting lead blocks maintain alignment and keep lines as close to the deck as possible. Cheek block has through-hub mounting for maximum strenth and the singles can be stacked to create a double.

Carbon black Acetal ball bearings. UV stabilised Acetal Sheaves. Alloy cheeks. Shackles are forged 316 stainless steel.

* Total block load. Maximum load on top sheave not to exceed 50% of total block load.

Low friction 2-stage ball bearing system provides consistent performance over the full load range. Hight static and dynamic load capacity. Light weight. Head posts of swivel blocks can be locked at 0 or 90 degrees. Cheek cut-outs for easy bearing maintenance. Removable becket pins allow lines to be spliced prior to fitting. Blocks can be dissasembled for servising or customisation. Max line diameter is 12mm (1/2"). Pin diameter on the post is 7mm (9/32").

Great for: mainsheet and spinnaker sheets on sportsboats to 36', halyard, vang and backstay applications on boats to 33', and various control line applications on larger yachts.

Cheek block has through-hub mounting for maximum strenth and the singles can be stacked to create a double.

Carbon black Acetal ball bearings. UV stabilised Acetal Sheaves. Alloy cheeks. Shackles are forged 316 stainless steel.

Stand-up base accepts a 3/8" post and 3/16" pin. Works with all Ronstan Series 40 blocks with posts (ie. not loop heads) and with only the singles with posts from Ronstan's Series 50. Base is a rhombus, 51mm x 75mm (2" x 2 31/32") angle-to-angle.

Use with Series 60, 75, and 100 blocks and RF324 Stand-Up Spring Kit for a hard-mounted stand-up connection. Four bolt-holes for 6mm (1/4") panhead bolts (not included).

Use with Ronstan Series 60, 75 and 100 blocks and RF2432-09 padeye for hard mounted stand-up connection. Yes, that's really the price. Ronstan assures us that it's a very high quality spring.

Take the shackle off the post of your block and replace it with this adapter to make a snap-shackle block. Accepts a 3/8" post and 3/16" pin. Works with all Ronstan Series 40 blocks with posts (ie. not loop heads), Series 50 singles (only, the post on the Series 50 doubles and triples is too thick), all posted Series 60 Ratchets, and the light load Series 75 Ratchet single (RF72100L).