I haven't used one but I see Sam's club sells one at a reasonable cost. I don't think it is brain surgery to make and assume most of them come off the same line in China. bumpy
Regards, Don My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.