Schaefer 51 mm 5 Series Block - Ball Bearing, 506-05 Brand_Gill Not all control line blocks

Not all control line blocks on a boat require two-stage bearings that evolve from years of R&D and the expense that goes with them

Ronstan snatch blocks are standard equipment on most sailboats

free-running

High-load carrying gears and caged roller bearings are made of 17-4 PH stainless for maximum strength

Pressure on the line engages the ratchet mechanism

Schaefer 51 mm 5 Series Block - Ball Bearing, 506-05 Brand_Gill Not all control line blocksLike the 5 Series blocks, but with Schaefer's ball bearing sheave. Curved ball races allow Schaefer ball bearing blocks to take higher loads than other similarly sized blocks. 5 Series blocks offer small to medium sized cruising and racing yachts an extremely high strength weight ratio resulting in a highly refined and reliable block. The versatile universal head design has a three way built in locking feature and accepts Schaefer "universal" adapters