The Speed Pull Magazine is not a typical Magazine mod, but rather a dedicated sleeve going around a weapon's magazine that allows for much quicker mag changes in the heat of the fight.
The Eagle Heavy is equipped with an Original Magpul® – 7.62 NATO by default, but it does not increase the weapon's reload speed, nor can it be equipped with the Speed Pull Magazine.
Due to it supporting a wide array of weapons, the Speed Pull Magazine is the first single modification to have multiple different icons.
The Speed Pull Magazine equips the AMCAR, Para, and AMR-16 with the Milspec Mag., but despite this they neither get increased magazine capacity nor reduced concealability, however it equips the Mark 10 with its Extended Mag and does give it increased magazine size, but does not increase stability nor does it decrease its concealment. Additionally, equipping the Speed Pull Magazine on the AK.762, Golden AK.762, and Krinkov will give them the AK's 5.45mm Bakelite magazine, despite the mismatched caliber.