Picture of an AN/PEQ-16A or PEQ-16B, used by the USMC
US Marine Corps
<a rel="nofollow" class="external text" href="https://www.trngcmd.marines.mil/Portals/207/Docs/wtbn/MPMS/0300-M16-1010_ZERO_A_MINI_INTEGRATED_POINTER_ILLUMINATOR_MODULE.pdf?ver=2015-06-15-120706-003">ZERO A MINI INTEGRATED POINTER ILLUMINATOR MODULE (MIPIM) TO A SERVICE RIFLE/INFANTRY AUTOMATIC RIFLE 0300-M16-1010 0300-M16-1007 (REV.)</a>