Dayco® combined the outstanding performance characteristics of the Dayco® Top Cog® Belt with the increased flexibility obtained through bottom-cog technology to make the most flexible heavy duty v-belt available. The raw edge construction maintains constant grip to eliminate slip and deliver maximum power on smaller diameter pulleys. The combination of top and bottom cogs offers extreme flexibility around smaller diameter pulleys for longer life. Polyester cord provides maximum tension-holding capability for the life of the belt. The Dayco® Top Cog® Belt meets or exceeds SAE J636 and J637 specifications.