Product: Profile GDH Titanium Crank Bolts May 24, 2011 got materials and some time open in one of their machines to make titanium GDH bolts for your GDH cranks. These bolts are made from 6AL4-v Titanium and come with a 7mm allen wrench GDH hole (even includes the allen for you) and aluminum GDH washers. Get on it since these will go fast.