Billet Dual Hose holder. You must measure the outside diameter of your hose you are using in order to match the dual hose holder ID. Size Chart is as follows.
Sizes are for the ID of the Billet Holder.
#10 = 5/8" or 15.9mm
#16 = 3/4" or 25.4mm
#17 = 1 1/16" or 27mm