Series 30 Ball Bearing Orbit Block(TM) - CheekBall 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 compactApplications: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 Dyneema(R)Specifications:Sheave : 30mm(1-3/16)Max. Rope : 8mm(5/16)M.W.L.: 300kg(660lbs)B. L.: 600kg(1,320lbs)Weight: 21g(0.7oz)