The Synchro blocks from Lewmar delivers performance achived by ball bearing blocks in pro racing but at a fraction of the price. A high-tech composite bearing combines high compressive strenght with an incredibly low coefficient of friction to deliver a free spinning sheave with enormous load capacity. The high density material, is self lubricating for long lasting, trouble free performance. An innovative Swivel-Lock head self-aligns to the angle of the line as it comes into contact with the sheave. SC50 Toggle fiddle block with becket and cleat.