The four rare-earth magnets hold it with 40 pounds of force. It is equally usable on drill tables and lathes, or other power tools with steel surfaces.
The 2-1/2" opening is compatible with standard shop vacuums; a 2-1/2" to 1-1/4" reducer is included for adapting to central vacuum systems and smaller portables.
For connection to 4" diameter systems, an 80" long by 2-1/2" dia. hose (with an integral swivel coupling) and a 2-1/2" to 4" adapter are available separately.
Patented. Made in Canada.