The Hyundai DURAWING 140 is a Concentric Overburden System designed for casing of 185 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 140 is the self actuating wing bit system that works perfectly everytime.
 
Drilled Hole Diameter: 185mm
Casing Size O/D: 168.3mm
I/D: 153.2mm 
 
Major Body Diameter: 152mm
Length: 566mm 
System Open: 185mm
Casing Size: 153.2 / 168.3mm
Total Weight (approx): 39kg
Hammer Type: DHD350, SD5, M50