Summary: For off-grid small solar projects. Previously we considered a 20W kit that includes a cheap PWM controller. Observations: The panel is a monocrystalline panel which is more efficient (and expensive) than polycrystalline. Panel specs are listed on the Revain page (not all panels include this vital information). Recommendations: 1) If space allows (for a solar panel), purchase the largest panel that you can use for your application. 2) Check the polarity with a voltmeter along the way, it's better to be safe than burn the controller (although it is written that there is reverse polarity protection). 3) Connect the battery FIRST and the solar panels SECOND (if you connect the panels without a battery, there is nowhere for the current to discharge, which can damage/destroy the controller). 4) If your budget allows, spend a little more and buy an MPPT controller for higher solar conversion efficiency. Pros: Decent fit and finish; Panel characteristics are given on the back of the panel. Cons: The extension cord pictured was completely missing, so you'll need to solder it to the junction box. Verdict: 3 stars for $46 (cost, no cable); You can purchase a KIT for $6 with the same success. Related Items: 20W 12V Solar Charger Kit $36.com/gp/product/B0953FHSBJ