"Yes, but" for this product, it only works under strictly specific conditions, namely when the car (windshield) is fully exposed to the sun, with all the long-term drawbacks that this entails. It has no suction cups or any kind of clip (not even a little light to show whether it is working), and you have to find a way for it to always face forward. A good hack is to place the sunshade behind it and use a steering wheel lock bar to keep it pressed against the windshield so it collects as much sun as possible.
It has a fuse inside the cigarette lighter plug and a good design so you don't mix up the polarity, with a long cable for inside the car.
The alarm draws power every day; this panel replenishes it (theoretically, more than enough) so that after, say, 15 days the battery has not "dried out" and you can start the car. However, if the car is in a narrow street and at some point it gets shaded, then you gain nothing, because in a few days the battery will die; the few hours of sun that hit the panel will only give a few amps to the battery, just enough to delay the "inevitable" by maybe 1-2 days. So you need to have the car in a place where it is constantly hit by the sun, e.g. on some big road with no buildings around, baking in the sun, getting covered in dust, keeping in mind that instead of 15 days it will last a few more, so you have to go get it, take it for a 30-minute drive to fully charge the battery (plus then wash it), and then where will you find the same good spot again? If you put it somewhere else and the sun does not hit it directly, then it is "zero for the total," so it is only suitable for a village or generally the countryside where there is space to find a spot, or if you have an open parking area in the yard and do not use the car often.
Do I regret buying it? Yes, because after two weeks or more I have to go pick it up from where it is, because even if it gets enough sun, around 10 p.m. I measure 12.47V, which by dawn will be lower, so what did I gain? I never go above 13+ to say I have a "positive balance" in amps.
Warning: if you forget and start the engine while it is connected, you have burned it and that's it; also first check whether the cigarette lighter has power with the key off, because if not, then you are forced to run the cable inside the car and onto the battery with crocodile clips.