labeling suggested the tube was recently manufactured. this tube is not a direct fit for K40 laser, although the tube can be run with existing equipment and power supply (cautiously). SELLER to CLIENT CARE is IMPRESSIVEShipping was excellent once product was in the system ! needs some works on dispatching the order. over all, generally satisfied. further, review tube is installed and tested!TO further, tube is installed(new mounts 55mm) and seems to work. (predominate purple light). Connection to the electrodes is a difficult task, as the terminals are TOO short(extending only 3/32") to connect properly.however, a spring (only) type Marquette could be used (done/siliconed). Soldering "ball type" is not recommended as fear of thermal upset is at risk. New 60 watt PSU installed. Full testing, when put into service, updates to follow