These washers are so simple, yet work so well for a long time. But, there's a secret to getting that return. You must condition them for use! Just Google how to do it. But, basically you squirt some oil all over it and massage it in to the leather. One thing the video shows is turning it in side out a couple of times to stretch it and work the oil into the leather. Just remember to turn it back to right side out!. This procedure makes a big difference in how well it seals.
I needed to rehab my pump and only after receiving this did I realize that I needed a 30mm washer rather than the 28 mm washer that I ordered. The 28 mm washer is up for grabs. Let me know if you want it.