【Feature 1】 1/4-Inch Heavy duty hexagonal center shaftfor use in quick change chucks 【Feature 2】 There is a spring drilled in the center of the high-speed steel to push out the cut chips , ensuring smooth and clean cut of the hole saw blade. 【Feature 3】Double metal strips and HSS teeth can be sharp and quick opening, reducing the opening time. Heavy duty hexagonal center shaft for use with any electric drill, no restrictions. 【Application】- Widely used in wood, corn hole boards, plastic, drywall, plaster, thin slate, acrylic panels, etc.