There are 40W laser tubes with glass exit mirror heads and with metal mirror

Lasers
,
1

There are 40W laser tubes with glass exit mirror heads and with metal mirror heads.

Does the head material matter?

2

A metal head is supposed to be better quality. I have never seen any data on it however.

3

Most metal head tubes use screw connection and not the crap pin

4

http://www.ebay.com.au/itm/40W-700mm-Engraver-Laser-Tube-Holder-Support-For-CO2-Cutting-Engraving-Machine-/201989686682?hash=item2f0786059a:g:dnMAAOSw-wFZbGGv

5

http://www.ebay.com.au/itm/40W-700mm-Engraver-Laser-Tube-Holder-Support-For-CO2-Cutting-Engraving-Machine-/201989686682?hash=item2f0786059a:g:dnMAAOSw-wFZbGGv

6

Is the metal housing of the totally reflecting mirror connected to the power supply red wire so the whole part is at high voltage?

7

That’s why the reci and spt tubes have silicon caps for hi voltage end