There's no better mainsheet block than the Harken Carbo Single. Laser Performance suggests you use this as the first mainsheet block on the centerboard trunk. It is a 40mm fixed block, and can be used as a becket block. Made of high strength resin, the Carbo is lightweight, strong, reliable and affordable. What more could you ask for?
Pair with LP91340 and LP91283 for a complete mainsheet system.
What's that? Looking to upgrade even further? Check out APS's Mainsheet Bridle, APS918.
This Part is also listed as H2650.