Ronstan Series 30 Ball Bearing Block Single Becket Option Lashing [RF35109HL]Series 30 Ball Bearing Block Single Becket Option Lashing Ball Bearing Blocks 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 fibre reinforced composites in the block head, cleat arms and beckets. Highest