Tapa de plástico Harder y Steenbeck.

It doesn't fit over the flanges around the Ultra's aircap which most needs a cap for backflushing because the cage-style aircap prevents you from pinching the needle tip. You don't get an airtight fit so backflushing with the cap sort of works but also sprays paint out from the cap and back along the body of the airbrush. It does fit over the flanges around the Infinity's aircap, but you can easily pinch the needle for backflushing with the Infinity so you don't need the cap unless you're nervous about touching the needle.

Bought this to reach $10 spent on an order. I had been suggested it prior by a youtuber and exspected it to be somewhat more special inside then outward appearance implied. In truth you could he using a marker cap or something and I found it to be very silly. Im only keeping it because its yellow.

Works good for back flushing, both for mixing paint in cup, and on cleanup, the only reason I gave it 4 stars is it not as well made as H&S other products.