Warranty: 12 months money back and free replacement. If you have any problems, feel free to contact us. We will respond within 24 hours and try to help you the best! Notice: Drilling method: use WET only. Rhinestones: In the use of the process must be added water, should be drilled to dig core engineering, the proposed matching fixed or hand-held drilling rig. Install the bit: first check the spindle has no swing, electrical and mechanical parts are normal, on the bit to ensure that the drill and drilling rig clamping, and maintain concentric. Application: Intended for drilling hard concrete, block, brick, masonry, and the like materials. It is suitable for drilling and coring of reinforced concrete, brick wall drilling, air conditioning installation, pipe, road signs drilling, expressway and other outdoor projects. This product is tested, thickness of 220mm cement block, inside four 14mm steel bar, play through about need 4 minutes, can play 40 holes. Hand-held drilling machine need 3-4 minutes to play through the brick wall (only for reference, different operating conditions will affect the bit working life). Specifications: Segment height: 10mm Bit Diameter * Bit Length: 51mm (2") x 370mm, 76mm(3") x 370mm, 102mm(4") x 350mm , 120mm(5") x 350mm Thread size: M22 (The thread diameter of the water drill is 22 mm) Package included: 4 x Wet Diamond Core Drill Bit (2" 3" 4" 5")