This is a leather pumping shaft for the Optimus 00 and 111.
It offers better pumping performance and is semi-permanent compared to O-ring types.
It also reduces wasted pumping.
You can simply remove the existing shaft cap.
The Optimus 00 can also be used with the Primus 210 and Svea 121.
The leather is made of ultra-high-quality, soft Korean cowhide.
It has a high seal, preventing wasted pumping.
The end aligns with the nut, improving compressed air efficiency.