Apem standard membrane keypads apem a03561 the apem 4 x 4 standard membrane keypad with insert pockets is a high quality matrix keypad with 16 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 a03561 ao 3561 standard membrane keypad 4x4 with insert pockets