The Hyundai DURAWING 365 is a Concentric Overburden System designed for casing of 425 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 365 is the self actuating wing bit system that works perfectly everytime.
 
Drilled Hole Diameter: 425mm
Casing Size O/D: 409.6mm
I/D: 387.4mm 
 
Major Body Diameter: 386mm
Length: 940.5mm
System Open: 425mm
Casing Size: 409.6 / 387.4mm
Total Weight (approx): 389kg
Wing Retracted: 363mm
Hammer Type: QL120,  SD12