We have tumblers that are hardened, tempered and ready to drop in the lock. However, our tumbler axles are turned to the exact dimensions recommended in the Siler instruction sheet. In prior years before we started turning all tumblers some assemblers of Siler lock kits turned their tumblers to different dimensions, and some didn't turn them at all. So, if your old tumbler is turned to 5/16" on the large axle and 11/64" on the small one, we can supply a drop in replacement. If your tumbler has different dimensions we will need to custom fit a replacement.