I just bought a Trail Lite B+ 211s with 8.1 Chevy engine. This is my fifth motorhome (others range from an old 20' Vagabond, and three Winnegagos, from 19 to 32'. This vehicle is fantastic. I am...
I think the two most recommended are the Progressive Industries one and the SurgeGuard, though I don't think the latter, in this model, has polarity tester. I know people have found them at better prices than on this site, so it might be worth looking around a bit.