When the laser is bright for a moment then goes dim, it means the battery needs to be recharged. Do not de-charge the battery! Use a 9 volt alkaline battery with the charging adapter suppled with your laser. Plug the adapter into the charging port at the bottom of the forearm ( se illus.). Do not activate the laser while charging! Remove adapter after five minutes. Ten Minutes maximum A good Battery will provide several recharges. If your battery fails to take or hold a charge, return the frame to the Factory. Do not attempt to change battery yourself.
This might not help if you don't have the charging adapter and can't get in touch with the manufacturer.If all else fails you may be able to take it to a battery store and they could probably make you a custom battery for it. http://www.law-17.com/instructions.html