PacTool Gecko Gauge Model SA903. Home siding installation kit for use with 5/16 inch fiber cement siding. 2 gauge clamps included in this kit. Great for use on one-person installations. These gauges can be adjusted at 1/4-inch increments for 4 to 8-inch siding reveals. Can be used on primed or pre-finished siding products. This is a new, unused set of hands-free clips for helping with install of fiber cement siding.