Theree are no real 50 watt co2 laser tube, whats being sold as a 50 is really a 40 watt tube pushed at start up to 50, tube is over driven and will not last. get a 60 watt tube, make sure of the length and Dia of tube is 55 x 1200mm = 60 watt tube.anything less is not a real 60 watt.
40W Laser Tube
Length=1010mm, Diameter=51mm