I made my own. My piston kept sinking on my chair, so I got some 40mm waste pipe I had lying around, cut it to length, then slit it once lengthways.

I put it over the piston (pulled the pipe wide enough to slide over the piston, not easy, but doable) and wrapped it with duct tape to stop it pinging off.

It is still there 5 years later.

Be careful with it.

I have an Elegoo Phecda 10W which at the time you couldn’t get the air assist for. So I designed my own air assist (similar to yours).

A test print caught fire (card), and this melted the air assist nozzle (PETG). This, in turn, covered the lens with PETG. While trying to clean it, I broke the glass protection. I now have a new air assist nozzle with an in built 20mm x 20mm glass slide cover to protect the laser. Not ideal, but Elegoo don’t have spares yet.

happy cutting though!