Needing no introduction, the product that started it all. The original Magpul!
 
When installed on the base of a 5.56x45mm rifle magazine, the original Magpul provides improved speed and controllability during high stress, tactical magazine changes.
 
Durable synthetic rubber loop with recessed rough gripping surface. Quick and easy installation and removal. Patented design based upon the tried-and-true para-cord loops and duct-tape tabs used by special warfare units worldwide.
 
An issued item under NSN: MAG001-BLK BLACK MODIFICATION KIT, GUN, WEAPON 1005-01-554-2868, it fits most aluminium, steel, and polymer 5.56x45mm magazines.