Holt Allen's Sliding Gooseneck - Square Base 7mm Groove has an 7/16 in. (11mm) wide x 13/32 in. (10mm) thick backing plate that is snugged with a rotating knob, which is below the gooseneck pin. It the slider fits into a 9/32 in. (7mm) groove. Holt also makes a sliding gooseneck that fits an 8mm mast groove (HA41143).
|Note||Backing Plate Width: 11mm|
|Additional Notes||Backing Plate Thickness: 10mm|
|Pin/Hole Diameter (in)||1/2|
|Pin/Hole Diameter (mm)||12|