Factory counterweight used on "straight" King and Benge tenors. Fits King 2B, 2B+, 3B, 3B+, 4B, Benge 170, 175 and 195. 1-7/8 inch diameter chrome plated disk. Useful for balancing instruments with detachable valve sections, heavy slides, or other front-heavy modifications. Supplied with King logo decals only. Also fits Conn instruments, but does not match original shape. May not fit some very early H.N. White / King models. Fits all other trombones with 3/8-inch (9.5mm) diameter cross brace in the main tuning slide. Weighs 0.40 pounds (0.18 kg).