Retainer Rings 3 pack of aftermarket lid retainer Rings Seals for 3 pound Thumlers barrels used on models T, MP-1, A-R1 and A-R2. They not only far exceed the OEM specs but also exceed any other ring you can buy. They are proudly made in America for Bar27 Innovations. If you dont agree its the best ring youve ever used return it for a full refund. Not the cheapest, simply the best. God Loves You!