Had this pickup tool break. I decide to take it apart and found the tube with a little work would make about a 32" blowgun. The tube is round except at the ends where they were pressed into open squares. Took a hacksaw and removed back till the tube was round. Now I am looking for something to make a mouth piece and muzzle protector. I think it is about .35 cal. The tube is steel on mine. Very rigid and smooth on the inside.