MULTIPLE SIZE - 2.5/4.0/6.0mm² three size indicator and most types of semi-insulated and fully insulated butt terminals connectors. WIDE CRIMPING RANGE- Special for MC4,the solar MC4 connectors crimping range is 2.5/4.0/6.0mm² / 26-10 AWG , applicable to most types of semi-insulated, insulated wire terminals and connectors, fits for various projects. DURABLE TO USE –The Solar Panel MC4 PV Crimper is Made of high quality 45# steel with the durable PP crimper handle. Carbon steel made hardened construction make it solid and durable. It can be used for a long time. HIGH QUALITY CRIMPER –Precision crimping module and integral locking design ensures high quality crimping when repeated crimping. LABOR-SAVING & SAFETY DESIGNED - Self-adjustable ratchet mechanism design for easy operation. Automatic Release don’t require a huge amount of grip strength ,device adds safety when in use.