The M4 Carbine's with similar weapons' different Grip Pod Systems, AKA "Grip Pods"  created in 2003 are still used by the American (Include the US Army, USMC, National Guard, US Air Force, FBI, CIA, DEA, Customs Border Patrol, etc), British and Australian armed forces is such a device. The grip may also have a tactical light and the control switches molded into the grip's assembly.
The M4 Carbine, along with similar weapons' distinct Grip Pod Systems, created in 2003, is still used by American (including US Army, USMC, National Guard, US Air Force, FBI, CIA, DEA, Customs Border Patrol) and British/Australian armed forces. The grip may also include a tactical light and molded control switches.