The Mansfield 39CH is a chrome all metal trip lever designed for the Mansfield tank models, 106, 192, 3106, 3987, and 2987. The only piece on the lever that is not metal is the locking nut, and threads for the nut. The locking nut provided with the trip lever is reverse threaded, which means turning it to the left will tighten it, and right will loosen it.