Arbors with ejector function for taking out the core easily. Arbors ending with EL are for Multi-Construction holesaws with All-round carbide drill included (Wood & Bricks). Arbors ending with ESM are for Bi-Metal holesaws with HSS drill included (Metal & Wood). Arbors ending with ES are for Carbide tipped holesaws with All-round carbide drill included (Fibreglass & Masonry). For enlarging existing holes you can aslo buy 3834-Upsize that is exceptional to use in combination with our ejector arbors. All arbors are packed in retail package