This is a mid 20th century nickel driving bit . The straight bar mouthpiece is half-twisted or reversible. The short cheeks can turn, each has two curb rein slots, the lower slot is hexagonal. One cheek is stamped "Silver" and the other "Solid Nickel"
The bit has its original nickel curb hooks.
There is a little wear where the cheeks pass through the mouthpiece.
