So there is no way these could actually handle 300 amps for more than a split second, way too thin. However as replacement clamps for a 100 amp battery charger they are just fine.Heavy duty and very well built. Hard to beat for the price.Used on a 48VDC Solar Battery Pack Charger. Simple to put on, good price, good medium duty set of battery cable clamps. I recommend. Bob Sterling, San Leandro, CA.Works well with my welderDesign is excellent. Separate terminal piece allowing you to connect the wire first, then screw the terminal connection into the handle. Makes it a much easier installation. No need to work on a fixed terminal inside the handle.Just what I needed to connect my inverter to my truck battery.CUESTIONEBLE LA CALIDA , PERO SI ESTA HECHO EN CHINA NO SE POR QUE ME SORPREDO,As advertised--all copper conduction paths i used to replace clamps on battery charger. Much better than OEM for transmission into battery big enough for even truck and boat batteries. Very simple to snip off old and connect these new and very sturdy connection as well.no me resultaron utiles para complementar mi sistema de carga vehicular. los devolví por esa causa.