Purchased this a few weeks back from this site. The battery ($12 at a local pharmacy) was DOA, significantly reducing the apparent savings off MSRP. The laser itself works fine. If you have a polymer frame it may be difficult to fit. One of the workers at my local gun range said that that is often a problem with metal accessories on a plastic rail. Although I eventually did get it on, it took a lot of effort to mount and remove from my S&W SD9VE.