I got two of these. One works fine, just don't try to over tighten the horn. It doesn't get very tight. The other was defective since the horn will not stay on the canister at all. It won't even get barely tight and just falls off. And it wasn't anything I did wrong. I read the instructions and used it just like the other. You have to hold the horn on, then after you sound it you're left with two pieces.And YOU CANNOT RETURN THESE TO AMAZON! They're deemed hazardous and you're not allowed to send them back. So, if you get a defective one like me, you're stuck with it.I wouldn't recommend this brand. And definitely don't purchase anything like this from Amazon. It was a rather expensive mistake for what the product is. Live and learn.