"PRETEC PCMCIA SRAM Card conform to PCMCIA/JEIDA international standard and consist of multiple very low power consumption CMOS SRAM ICs, decoder IC and power control IC mounted on a very thin printed circuit board using surface mounting technology. With the dual back-up battery design, each SRAM card contains a replaceable but non-rechargeable 3V lithium battery and an on-board rechargeable but non-replaceable battery for data retention. There is also a battery case lock system to prevent battery dropping from the card. "