The Desert Tech QTRLR15B53, also known as the Quattro-15 lower receiver, is uniquely designed to accept the Quadmag-53, a special Desert Tech 53 round magazine. It is also highly compatible with standard AR pattern magazines. This lower receiver features drop-in capability with all standard AR-15 upper receivers. The Quattro-15\'s capacity to hold 53 rounds per magazine makes it possible for individuals to carry a significant 210 round loadout. Notably, this large loadout can be achieved with only 4 magazines, rather than the typical 7.