Ball bearing blocks deliver sensitivity to hand held loads. This 40mm triple block with cam cleat is ideal as part of a system for mainsheets, backstay systems and other control lines that require significant purchase. The smaller sheaves are compatible with up to 3/8" Sailors can detect changes in wind intensity and direction by feel. Hand held loads of the main and headsail, spinnaker and other control lines communicate valuable information to the crew. Lewmar Control Blocks are designed to keep these lines of communication open. By using ball bearings, Control Blocks assure sailors that small signals won t be lost in unnecessary drag or friction. These light weight blocks are ideal for control lines and other hand-held loads. Long fiber technology used in the construction of the composite cheeks adds strength while keeping the overall weight down. An open design is used in the cheeks to reduce maintenance: saltwater and sand can be easily flushed from the block and the bearings lubricated. The sheaves use the same long fiber technology for strength and feature a metal insert for the bearing surface. This addition improves performance and longevity. Line size compatibility and safe working loads are indicated on the sheave of each block to avoid failures caused by overloading the block. Get the messages your boat and sails are sending you loud and clear with help of ball bearings and Lewmar Control blocks.