I've been using these helmet mirrors for many years, and rely on them continuously to keep aware of what may be coming up from behind, be it a pack of riders, a fast moving car, or a large truck. I have now supplemented this awareness with a Garmin Varia rear tail light with radar. The combination works great to keep me as safe as possible on the road. Only draw back is when I get off the bike and take off my helmet, I still find myself just tilting my head to see behind me, forgetting the mirror is no longer there.
I have tried other detachable rear fenders and this was the most well designed because the parts that attach to the seat-post are very strong and the actual fender material is extremely thin and light. Since it is deflecting rain and mud etc., it is sturdy enough for those sorts of things.
The other thing that I like about this fender is that it does not shift around all the time like other detachable fenders. I think because it is made of very light thin material, if the bike gets a lot of torque left or right, the fender hangs on the seat-post better because it has very low mass.
This may be too niche a need for most people, but the Ottolock has worked perfectly in the manner I have used it. I bought the lock to carry on longer training rides this winter, while I was in Italy (90 days). Not living here full time, I have often felt nervous in the past, when I made these stops. I felt like my head was on a swivel when I did stop, always anxious about my bike's security. Now I feel assured that my bike will still be there when I'm ready to ride again. I really like the weight ' I have not noticed it in a jersey pocket when riding ' it's surprisingly light. The lock is quick to secure the bike, and quick to go back in a pocket to resume my ride. I wouldn't use this type of lock to secure the bike for long periods of time, but for a coffee break or run into the store for some Haribo, it has been exactly what I was looking for.
I've used the original design for over a year with a few different saddle and post combos including carbon to aluminum rails and this has always been reliable. There was a great sale recently and I bought the Tropical Feather and I fell in love with the design and the added color to my bike. It disappeared yesterday on about the 5th ride it's been used.
This was a big surprise because I had this mounted correctly and it was bomber tight. There were some strong cross winds that must be responsible.
Now I really want another Tropical Feather for my bike, but I wonder if that wasn't part of the problem as the feel of it wasn't completely the same. I may decide to stick with the basic design since that has proven 100% reliable so far. No, I have to try one my Tropical Feather first to see if that was a fluke it really adds a nice touch! Darn it that it's gone already! Feathers are made to be lost so it is fitting.