Despite being a pretty dowdy looking red light, this tail light is bright as hell. Almost concerningly bright, in that I'm worried I'm distracting--rather than alerting,,motorists while riding in traffic. I actually mounted this in a way that slightly angles the light down so I'm not flat out blinding people behind me! Far as mounting, I had no problem mounting this on the back of a common Topeak Explorer rack with the included mounts--this was much appreciated, as many bike lights are difficult to mount when racks are present. This was a big selling point for the light. Far as modes, you get solid or a couple flashing modes. This light has one button and you have to cycle through the modes every time you want to turn it off from strobe flashing (always the setting I use for riding in traffic). This is a mild annoyance. The button itself is mounted on the rear of the light, which could be a problem for some types of bulky rack installs, but on my standard Topeak rack it isn't a problem and I can still hit the button just fine with gloves on in the winter. I've put this through pouring rain several times and not had a problem, however note that when you pull the light apart for a battery change, you'll need to take care with the very thin gasket between the lens and light body, as that's what keeps it water resistant. Batteries were included, but were not fresh and only lasted a couple months. We'll see how this light lasts with fresh Procells in it now. I strongly prefer tail lights with standard batteries because they last way longer and give you more options than a built-in lithium (you could always put in some rechargeable batts if you want), but mainly I just don't want to have to worry about recharging yet another device all the time. Overall, while not a 5-star product, it's not a bad light for the price. The Grateful Red is simple, basic, meets my mounting needs, and is, for better or worse, very bright. Update: apparently this thing is Ms. Pacman to batteries. Here we are a couple months later and I'm replacing the batteries again. When they die, it happens fast--from bright to dead within maybe an hour of run time. I use the light about 40 minutes a day 5ish days a week for commuting, always on flash mode, and I remember to turn it off when I park. Other bright AAA or AA taillights I've used in the same application have lasted 6-9 months between changes and sometimes better, so I've knocked a star off this one. Update 2: I get best battery life using the freshest, top quality batteries I can find. If they're halfway through their shelf life, you get a couple months. Fresh alkaline batts that have expirations more like 6 years from install do last much longer. So if you bought your batteries on sale and they don't have the best expiration dates or are off-brand, use those for remotes and computer mice and use something fresher and higher quality for this light like Procells or at the very least copper tops. I think this light probably needs particularly good current delivery so is sensitive to battery quality. Haven't tried lithium batts yet but that might be a good option too.
