A SHALL concrete siding cutter (or shear) is a handheld electric tool designed to cleanly cut fiber cement siding (like Hardie board) and backer board with minimal dust, using a double-cut blade that creates a curled waste strip instead of dust. Key features includes variable speeds (up to 2700 SPM) for control, and a lock-on button for continuous cuts, making it efficient for straight lines, curves, and irregular shapes.