Dual Mags decreases the time needed for every other reload action by using two magazines taped together. Every odd reload (e.g. first, third, fifth, and so on) is faster. The following reload will be the default, original reload. The odd reload depicts the player removing the spent magazine, flipping it around, and inserting the second, fresh magazine.
With the exception of the RPK, the attachment also gives the player two extra starting magazines when the player spawns. For example, the FAMAS, with a magazine size of 30, starts with 90 reserve rounds normally, but with Dual Mags it starts with 150 reserve rounds.
Since it speeds up reload times and provides more ammo, it reduces the need for Sleight of Hand and Scavenger (however, using either or both perks can increase the immediate usefulness of this attachment). However, it should be noted that Dual Mags used with Scavenger Pro does not grant extra ammunition, using Dual Mags with Scavenger Pro will only grant the benefit of a quicker alternate reload. Because of this, it is a strong attachment choice as it opens up Tier 1 and 2 slots to other perks such as Flak Jacket and Hardened to maximize the potential of the player's loadout.