ProLiant BL685c G5 (DDR2-800MHz) 1GB PC2-6400 DDR2 Memory Compaq ProLiant BL685c G5 (DDR2-800MHz) RAM-1GB 240pin PC2-6400 DDR2-800 800Mhz Registered ECC DIMM. The price is for a single stick all systems require this memory in matching pairs must buy and install 2pcs FOR A KIT BUY Qty 2.