AN/PEQ-15 Laser Device
The AN/PEQ-15, also known as the Advanced Target Pointer Illuminator Aiming Light (ATPIAL) is a laser aiming / illumination device that is typically mounted on personal weapons such as M4a1 carbines.
The AN/PEQ-15 is part of the Block II iteration of the Special Operations Peculiar MODification (SOPMOD) program which provides a range of accessories for M4A1, MK18 CQBR, MK16 SCAR-L and MK17 SCAR-H rifles, among others.
It is similar in function to the AN/PEQ-2, which was an element of the original SOPMOD package, but comes in at nearly half the size and weight as its predecessor. Unlike the PEQ-2, which only worked with night vision goggles (NVGs), the PEG-15 can also produce a laser beam that is visible to the naked eye.
The beam can be set to narrow and used for aiming / target acquisition or to wide and used as an area illumination device.