Main Tufnol pulley/sheave. Used inside a hot air balloon for a control line. Never exposed to fresh or salt water, always lightly loaded and never under constant tension. Clean with lots of service life left.
The block sides and pulley wheel are made of
Tufnol. Measures 3 11/16" long overall. The sides measure 3" x 1 7/8" x
1 3/16" thick. The pulley wheel has a 1 3/4" o.d. and is 1/2" wide.