This is the most common and current transformer for the Bliss 15 with green and blue lasers. The older models used a 24 volt transformer and a replacement for those is only available by having the factory convert the unit to the newer 12 volt transformer. If you have a different appearing transformer email the details on it to shop@lasersandlights.com for confirmation you are ordering correctly. Transformer types are specific to certain units as determined by the serial number.  ONLY for use with BlissLights Bliss15.