https://www.drillingsupplystore.com/drill-bits-ql-60-dth-rh450-6in-concave-face-spherical-button-155mm-61-8inch.html
Drill Bit QL 60 DTH-RH450-6in Concave face / Spherical button (155mm 61/8inch)
QL 60 DTH-RH450-6in Concave face / Spherical button Applications: 1.Soft to medium rock 2. Abrasive (Diameter 155mm 61/8inch, Weight 26Kg 57lb)