Davoli Tube amplifier safely ventilation grid

Different models of Davoli tube (guitar/PA) amplifiers from the 60-tis or 70-tis use tubes as EL504.
These have 450 Volt on the top of the tube
The original ventilation grid is often damaged by the heat
So then it's easy to touch the 450 Volt with your finger (Don't do this !)
Protect the round cut in the wood with this new lasercut ventilation grid
It's important to use POM as material (up to 150 ºC, strong) and do not use acrylic (that can't stand the heat / easily damaged)