For the K40 laser, it has 8 5mm white LEDs and is held in place with small, powerful 4mm magnets, making it quick and easy to adjust. The magnets are easily found on Amazon, and the LEDs can be found at any electronics store.

The laser beam from the machine passes through the hole in the center of the LEDs! The LED connections consist of two groups of 4 LEDs each, connected in series (so 4 LEDs will be connected + to - and their ends to 12V, the same for the other 4... doing so, each LED will have 3V for proper operation!)

I used the masking tape seen in the photo to provide a reference for the laser beam so I could center the hole where the LEDs are...