https://www.mrosupply.com/speed-reducers/96714036_30728003_boston-gear/
Boston Gear 30728003 SSHF726-20KC-B5-HS5-P23 Stainless Steel Worm Gear Speed Reducer 20:1 Ratio...
Boston Gear 30728003 SSHF726-20KC-B5-HS5-P23 stainless steel worm gear speed reducer, 20:1 ratio, 2.6" center distance, 56C input, 1-7/16" hollow bore.