The true material of the cannon booms is sch.5 stainless pipe... The OD is a perfect fit to the body...The only downside is the ID is a little off from cannons inserts on the pulley end.... But 5 minutes on a sander and problem fixed..I just bought a 5' stick last week for $25 each...the cannon tube is Proprietary to them never been able to match the ID...sand the plastic of the pulley insert...not the stainless....