Azonic 454 cranks have chrome plated Chromoly arms. Comes with 4130 Chromoly spindle and a sealed euro, mountain bike style bottom bracket. Will work with 68mm and 73mm width bottom bracket shells. Comes with a choice of 3 different spiders: 110mm 5 bolt, 104mm 4 bolt or a 94mm x 5 bolt spider. Intended use: DH riding. These cranks can handle serious abuse. Very easy to set up. Comes complete with directions. Like the MRP Bones and Profile, you can achieve the perfect chain line by simply adding or removing spacers to the spindle on the chain ring side. With these cranks, setting up DH chain guides is a breeze. Leave some hair to help absorb impacts!