Apem standard membrane keypads apem ac3560 the apem 3 x 4 standard membrane keypad with insert pockets is a high quality matrix keypad with 12 pressure pads that have only outlines and symbols printed on a flat flexible surface the clear windows have a silver perimeter embossing a silver unembossed border on a black background while four inserts with black graphics on a silver background are also supplied apem ac3560 ac 3560 standard membrane keypad 3x4 with insert pockets