Series 30 Ball Bearing Orbit Block(TM) - Single - Becket - Lashing HeadBall Bearing Orbit Blocks(TM) boast the highest strength-to-weight ratio available. This is achieved through all-composite reinforced polymer materials and multiple attachment options. Their precision design provides the optimum number of ball bearings for minimum friction while weight reduction is achieved through the use of fiber-reinforced composites in the block head, cleat arms and beckets.Features:LightweightHighest working load in its classSecure, versatile and secure attachementLow profile and compactUltra low profile thru-sheave becketRF35101 accepts RF1850S shackle in both orientations to create a conventional loop top blockSelf-lubricating NylatronA(R) sheave and full contact bearing for high dynamic loadsApplications:Mainsheet systems and spinnaker sheets on dinghies to 5M(16')Halyard, vang and backstay applications on boats to 5M(16')Control line applications on larger yachtsMaterials:Sheave: High compression strength carbon black AcetalBall Bearings: High compression strength AcetalFrame/Cheeks: Toughened, glass fiber reinforced NylonLink: UV stabilized, multi-strand impregnated SK75 DyneemaA(R)Specifications:=Sheave : 30mm(1-3/16)Max. Rope : 8mm(5/16)M.W.L.: 300kg(660lbs)B. L.: 600kg(1,320lbs)Weight: 22g(0.8oz)