The RS808 is Roland's TR-808 Rimshot/Clavs

The RS808 is Roland's TR-808 Rimshot/Clavs sound generator adapted for modular synthesizer use. The front panel contains all of the controls found on the original TR-808 drum machine, allowing you full control over the sound’s volume levels to mix with other drums, and accent levels. In addition to that, the RS808 includes a Pitch control knob, Snap control knob, and two switches for selecting between four different sounds.

http://www.tiptopaudio.com/rs808.php

• 14 mA +12V
• 13 mA -12V
• 0 mA 5V
• 36 mm Depth

No info about availability.