From the Manufacturer
Stabila Magnetic Plate Level extends from 7 to 12 feet and is designed for the residential framer or any contractor that needs fast and accurate wall installations (plumb plate to plate) or wide horizontal projects. The magnets have incredible holding power and will confidently hold the Plate Level in place on steel while you work “hands free”. Guaranteed accurate for life, these extendable levels are extremely accurate and extremely durable. Made in Germany.
Hands Free: Vertical, Horizontal, Overhead. Fully sealed solid rail (six sided) extension eliminates deflection. Frame side opposite the stand-offs a level measuring surface & straight edge. Vials are guaranteed for life never to fog, leak or require adjustment. Certified accuracy in the top read position: 1/32″ over 72″