This is the BernieDawg Midicap "silent" damper cap for the Coleman 530, M-1941, M-1942, M-1950, Coleman 521, and Coleman 523 US Military Spec stoves. It also is a good choice of silent cap on the Primus and Optimus 96 and the early MSR XGK II (not XGK EX). The cap will reduce the sound volume level of any stove it fits by a substantial amount, about 1/2 of normal sound volume levels at high flame, more reduction at low flame. It's the original mid-sized silent damper cap for mid-sized stoves and it's still the best. Any other imitations you may see are unscrupulous copies of lesser quality.