We offer high quality diamond core drill bits for concrete in various sizes and applications. TOC LongBuddy concrete drilling bits are 14" long and can be extended 12" at a time to allow deep drilling. They come with 1/2" to 16" in diameters and can only be used with water. TOC Pro dry concrete core bits are designed to drill hard, and reinforced conrete dry or wet with hand held grinders. TOC BLOC dry diamond core bits are for contractors to drill concrete and masonary blocks.