Universal Drill Compatibility: Instantly mounts into any corded or cordless drill with a 1/4” (6.4 mm) chuck. Ideal for job site flexibility—switch between drills without recalibration. Lightweight Powerhouse Design: Aircraft-grade aluminum frames slash tool weight by 40% vs steel competitors, while maintaining rigidity for 20-gauge (1.02 mm) galvanized steel and stainless steel. Adjustable Diameter Range for Every Task: HC1 Model: 2” to 12” (51–305 mm) holes – Perfect for electrical conduits, plumbing vents, and compact ducting. HC2 Model: 2” to 20” (51–508 mm) holes – Tackle large HVAC installations, automotive panel fabrication, or industrial venting. Precision Dual-Scale Guidance: Laser-etched English/Metric gauge on the pivot slide ensures ±0.5 mm accuracy. Set exact diameters for PEM fasteners, pipe fittings, or custom brackets in seconds. Cross-Model Part Standardization: Both HC1 and HC2 use identical mill-type cutter bits and replacement parts (HC1B pivot pins, bearings). Reduce inventory costs—one set of spares fits all tools.