| Recently Top Drill has developed overburden system to be adapted to soft conditions and very hard formation. This can allow simultaneously case the drilled hole. The patented Top Reaming Bit is a revolutionary new bit design. When drilling into the ground, the Top Reaming Bit extends out wider than the casing. Once the drilling is complete the Top Reaming Bit withdraws into the casing. The Top Reaming Bit outperforms all other competitors in the field. Top Reaming Bits have been applied for DTH Hammers and Tornado Hammers. | 
