<http://schema.org/description>
"Lewmar's 60mm and up Synchro foot blocks feature alloy cheeks, fixing isolators and molded baseplates to prevent sealant ingress into the sheave. Jamming aluminum foot blocks are designed to hold light hand loads only. They have a wide head that creates a solid base, so the block will not  inroll in around on deck. They are available as standard or jamming blocks and can be stacked to form a double foot block.The 90mm have hole spacing of 2 23/32 in. (69 mm) and require 2x 3/8 in. (M10) FH fasteners."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.apsltd.com/90mm-synchro-single-footblock-jamming.html>