It is a kind of valveless high air pressure DTH hammer with foot valve. 

Valveless air distribution hammer, more reliable of air distribution.

Good sealabIlity, no water and cuttings entering into hammer in water exists drilling.

 DHD and COP Series DTH Hammers Features:

1. Valveless air distribution, more reliable.

2. The simple design of the piston. Long life span.

3. More efficient energy transfer, faster drilling speed, low air consumption, and lower oil consumption.

4. Fewer internal parts, simple structure, long life span, less failure and easier to maintain because all the parts are heat treated.

5. Easy to disassemble because the top sub, the drive chuck, and the external cylinder are connected by multiple steps thread.

 DHD / COP Series DTH Hammers Advantages:

1. Simple and reasonable design, easy to assemble and dis-assemble, low problem rate.
2. Low air consumption, smooth drilling, maximum impact power, high penetration rate.
3. Multiple precise heat-treatment with all hammer parts to provide long lifespan under roughest working conditions.