AM9101BPC / P2101A Ram is 256-word x 4-bit Static Ram and is 1024 bit SRAM Random-Access Memory organized by 256 words by 4 Bit. DIP-22 Pin .4 row Package. We test 100% of our RAM. This is used in many arcade games such as midway Galaxian, Tron, Centipede, Millipede and many other MCR games and can also be used to replace all of the following 2101A, C2101 and if your replacing the faster AM93422PC or AM93L422APC let us know as we can supply them at your request so just add a note to your order. NOTE: Most of our stock is the 93422 or 93L422 so you may get them which is better and faster.