I find it difficult to trust this product to function properly. The knob that allows you to connect of disconnect the battery also controls the only thing that keeps the product from falling apart into two separate pieces. If there's any force at all on the battery cable, it could cause it to reconnect the battery on its own, even if you switched it off. If you unscrew it a lot to avoid this, it's likely to separate into two pieces, one left on the battery the on the on the battery cable. I trieSee full review