What the hec is this?

This is from a 1955 house which looked and worked like a 1955 house. Original owners.


I saw one of those behind a dishwasher via an access panel from a bathroom closet the other day. It looks like a pressurized can to help eliminate water hammer. It probably has a bladder inside.

I think so too…water hammer arrestor from another era?

Similar to this one:


i concure with the hammer supressor. the little tire valve on the end allows you to adjust the air presure in the little bladder inside as you see fit. there installed fully charged (with about 15 psi) and as you test it, let out a little air at a time untill the hammer goes away. also acts like a tiny expansion tank so your supply lines (PB) don’t burst (as much).