Product details:

PacTool International SA903 Gecko Gauge, Fiber Cement Siding Installation Tool (1 Set) ONE-PERSON INSTALLATION - working as a pair, the gecko gauge fiber cement siding tool supports fiber cement-board siding for one-person installation with virtually no layout time | USE WITH FIBER-CEMENT SIDING - use the SA903 gecko gauge siding tool with 5/16 fiber-cement siding, including James Hardie's updated HZ5 series with new eased drip-edge profile | ADJUSTABLE - gauge is adjustable at 1/4 increments for 4-8 siding reveals | PATENTED FRICTION-CAM MECHANISM - supports full 12' fiber cement-board siding lengths | WON'T SCRATCH OR MAR - heavy gauge plastic won't scratch or mar pre-painted siding Gauge Gecko 5-8 Inch 2 Pack