These 12mm Hex Adaptors allow you to attach 12mm hex drive wheels to 1/4" drive shafts. Simply insert a 1/4" shaft (D-shafting is recommended) into the adapter and tighten the set-screws.
Hex is 6mm deep. Overall length of the entire hub is just over 26mm. 1/4" bore for common D-shafting used in pullers and our Evolution pulling sled. Inc