Working as a pair, the Gecko Gauge clamps to each siding course, acting as a second set of hands to gauge and support the next course for nailing. Get fast, accurate one-person installation with less fatigue and with virtually no layout. In recent tests, the Gecko Gauge was recognized as the fastest and simplest fiber-cement siding tool of the popular brands tested. Take your siding installation to the next level with the Gecko Gauge!