Ever had to plumb from floor to ceiling by holding two levels together? If so, you might want to consider the Irwin Extendable Level. It consists of three aluminum I-beams that slide against each other; the center beam contains vials. The parts move and lock with a grip release. Since all three beams slide, the level can grow to be quite long: The 4-foot model extends to over 10 feet, and the 6-foot model extends to over 17 feet. Offset ends allow for point-to-point plumbing even though no single beam runs full length. In addition to the 4-foot and 6-foot models, a 5-footer is available.