The T-Models have a welded earth displacement head. Longitudinal grooves displace soil sideways and allow piercing even in hard ground conditions, a feature, which makes the combi head (KOK) superior in comparison to any other stepped, conical or “crown” head tool. The cutting and demolition edges destroy all obstructions regardless of whether they hit sideways or head‐on, providing the highest obtainable accuracy of the mole. The star chisel makes the combi head (KOK) superior in demolishing obstructions. The star chisel penetrates through every breakable obstacle. The welded head ensures a long life of the part – no moveable parts that can wear out.