The Auger Drive & Bits is engineered with "in-Line" drive design, to elimiate shain and sprocket reduction. A hydraulic motor drives the auger through a sealed planetary gear reduction. 
 
Specifications:
Model: ADB-13-1218R
Comes with (2) Auger bits dimensions: 12" and 18"
Effective dorking depth: 35"
Output Shaft: 2.56" round
Hydraulic Flow Required: 8-22 GPM
Max. Cont. Operating PSI: 3000 psi