Draper 43716 Diamond Core Drill Bit 152 x 170mm. Designed for dry cutting and suitable for use on most masonry applications including brick and concrete blocks these diamond core bits are popular for use in the plumbing electrical and general building trades. It should not be used in hammer mode. If the unlikely event that you do need to return an item we offer a 30 day return period for not needed / unused items. Excellent service and product. We use different couriers depending on the product(s) ordered.