These barrels are used in many “Standard” faucets made from the ’30’s up to the ’60’s. The actual stem lengths vary, but the barrel length and diameter remains the same. These measure 1 1/2″ long and 7/8″ diameter. These have been redesigned with an o-ring seal to help seal up the barrel to the valve body. This part has the seat of the faucet built into the bottom of it, and the entire barrel must be replaced when the faucet starts to drip.
Standard faucets with Cross handles normally take 2 hot barrels (handles MUST both turn in same direction when being opened), Standard faucets with Lever handles normally take one each of hot and cold.