Rec-mounts Shimano E-tube Cockpit Junction Box - Sm-ew90 A/b Adapterdi2-ew90 It is a component exclusive for REC-MOUNTS(TM) ,Please buy from the manufacturer detail page ,Can not be mounted on other manufacturer's mount for Shimano Di2 Junction SM-EW90-A / SM-EW90-B Material resin Please look at the compatibility chart , If there is no description please contact the manufacturer