The Model D- is analogous to the O-, in that it's a smaller size variant of the Model D.
Specs:
Sensor: Pixart PMW-3360
Main Switch: Omron (Mechanical rated to 20 million clicks)
Number of Buttons: 6
Cable: Ascended Cord (Ultra-flexible)
Mouse Feet Type: G-Skates Premium
DPI Indicator: Yes
Remappable DPI Button: Yes
LED Color: 16.8 Million (8 effects)
LED Adjustable w/ Software: Yes
Length, front to back: 120mm
Height at front: 33mm
Height at mid-hump: 40mm
Width at front: 61mm
Width at Mid-back: 67mm