Oregon replacement breaker punches for old style Oregon and Herr chain breakers. Breaker punches are made from heat treated steel which is incredibly hard, but brittle. They will break if not lined up perfectly. We recommend carrying a few extra just in case. This punch fits only the pre-2000 Oregon and Herr breakers and works on all chain except 3/4" pitch harvester chain (Bailey's old part number 45415.)