The present disclosure provides apparatus and methods for coupling an item to another item. The apparatus comprises a coupler mounted on the item and comprising a mating face having a plurality of catches thereon, the plurality of catches comprising at least one complementary pair of catches positioned and shaped to be engaged with corresponding catches of another coupler having an identical mating face when mating faces of two couplers are facewise engaged with and rotated relative to each other to align with each other. The coupler may be implemented as a floor plate of a magazine, as a clip, or in other forms.