Arrived quickly, Purchased as Replacement for K40 Laser Engraver as power supply had burnt though transformer casing, also replaced Power supply at same time as advised, I have had the K40 since 2014 and this is the first new laser and power supply it has needed. It has had plenty of use usually on high power cutting acrylic sheet 3 - 8mm with homebrew air assist. Would have purchased a spare Power supply but now Discontinued on Vevor. Main things to remember when fitting is take your time, clean near connections with Acetone or Isopropanol and alow to dry, do not solder, wrap joint and silicon seal. Main thing is to keep laser cool during use, below 20 deg C, I add frozen bottles of water to water tank which has a little antifreeze added.