Interdimensional Technologies

Devices designed to access, traverse, or manipulate the spaces between dimensions, ranging from theoretical "gap drives" that would let you slip between realities to more practical tools like the "interdimensional key finder" (which doesn't work, but sounds impressive). These technologies promise to solve the problem of lost items (retrieve them from the dimensional gaps where they fall), explain mysterious noises (sounds leaking through from adjacent dimensions), and potentially allow communication with beings that exist in the spaces between. The main challenge is that interdimensional technologies have to function in spaces where normal physics doesn't apply, which makes quality control a nightmare and warranties essentially meaningless.