Excel masonry drills are specially engineered for drilling granite, marble, cuddappah, ceramic semi precious stones & many other hard and brittle materials. Excel masonry drills have uniform and high diamond concentration, permitting fast and smooth cutting action without exit chipping. They are simple to use and fit any portable electric drill. Available from 5mm to 100mm dia. Supplied with instruction leaflet. - Diamond coated core drill bits are for marble,granite, glass,hard plastic,composite material,ceramic carbon,borosilicate and hard and brittle materials. - Make hundreds of holes using water as lubricant and coolant. - Premium sieved diamond grit is used with nickel as a binder used on a suitable steel shank for precision and long life. - Product of Excel Impex Made in India Side slot is provided for easy removal of cut material.