I was given this light by a good friend who had this mounted on a rifle. It had a tape switch on the rear cap which went bad. I have emailed Malkoff and Surefire and neither claim to have made this light. It is very well made everything is threaded and "O ringed". It appears to be a 6 series light using 2 123 batteries. I would guess it is about 10 years old or older.