A simple key to bleed the air out of radaiators.

The hole is 5mm x 5mm which is correct for all of the radiators in my house.

This is the first thing I have designed from scratch and printed on my new printer, so the construction is really simple.

Just print and use.

In my experience I had to tidy up the edges with a file before it would work propperly, but this might just be bacause my printer is not fully calibrated and some of the fill oozed out through the layers.