HPE 16GB (1x16GB) Quad Rank x4 memory is a single DDR3 DIMM for server memory expansion. The catalogue reference is RP001227414; HPE identifies OEM part 500666-B21 as a registered memory kit.
It uses PC3-8500 DDR3-1066 memory, with quad-rank x4 organization and CAS-7 latency. The listed module has a 240-pin DIMM form factor and a 1066 MHz clock speed, making those details useful when matching it to a supported memory configuration.