All steel, matte black & chrome. Parts with two patterns listed are dual bolt pattern wheels. Inside nubs for 17" & 18" caps is 7"; inside nubs for 20" cap measure 7 1/2". A cap is included with all wheel sizes. C52 cap is the only cap that fits 20". NOTE: 17" & 18" options have a ring around the hubcap area; 20" options do not. See Series 513 for 20" center detail photos. Doesn't fit Jeep Samurai. Lug nuts not included. Please check fitment before mounting.