The HD99 is the most powerful earthdrill in the Ground Hog line. With it's 9hp Honda or Subaru engine, the HD99 can easily dig with any Ground Hog auger up to 18 inches in diameter. The use of hydraulics allows the HD99 to have variable auger speed and reverse which is very useful if the auger gets stuck.
| Auger Speed | 140 rpm @ 3600 engine rpm (no load) |
| Auger Torque | 275 ft. lbs. torque (approximate) |
| Maximum Depth | Depends on length of Auger |
| Weight | 295 lbs. (134 kg) (with fluids) |
| Length | Normal Drilling 100 inches(253 cm) |
| Length | Close-up Drilling 75 inches (190 cm) |
| Width | 34 inches (86 cm) |
| Height | 38 inches (96 cm) |
