?The SDS-plus hammer drill bit F4 with its patented 4X stepped profile and patented tip. Low wear, very long service life. High efficiency drill bit for heavy-duty drilling in concrete, natural stone and brickwork.?StrengthsEfficientFastPrecise for dowel holesPatented carbide tipExcellent centering propertiesPatented 4-step profileFast drill dust feedLow wear, very long service lifeHeavy-duty drilling in concrete, natural stone and brickwork