4" long.  1/4" chuck size.  1 per pack. 

• Added durability- Hardened carbon steel for strength through the cross-section.
• Starts on contact- Split point pilot drill for faster penetration and less walking.
• Simple plug ejection- 7L arbor is designed with sliding pins to easily eject plugs from hole saws.
• Easy to use- Power groove shank allows arbors to be used in LENOX Uni-Drive Quick Change System. 
• No tool changes required (3L, 5L, 6L and 7L).
• Fits arbor number 1L, 2L or 4L.