The Hyundai DURAWING 745 is a Concentric Overburden System designed for casing of 842 mm diameter holes through varying formations into bed rock.
The wing bits are enclosed making them the most professional & efficient system on the market today as they are not exposed to "clogging" in loose overburden material while drilling down to the bedrock.
When the drilling starts, the bit wings protude utilising a unique cam sliding mechanism. The key feature of the DURAWING 745 is the self actuating wing bit system that works perfectly everytime.
 
Drilled Hole Diameter: 842mm
Casing Size O/D: 813mm
I/D: 781mm 
 
Major Body Diameter: 776mm
Length: 1219mm
System Open: 842mm
Casing Size: 813 / 781mm
Total Weight (approx): 2301kg
Wing Retracted: 744mm
Hammer Type: N240