I bought a handful of these from Zéfal France.
It turned my totally useless 40 year old pump into a fully functioning but woefully inadequate air pump. If you want to restore your original pump, this is what you need. Pump was from my '79 Moby 50V. $3.00 each, mailed in an envelope.
($3 is for just the replacement diaphragm, not the pump!) (edited)