I'm lucky enough to have a few bikes. I have a saddle bag with what I need in it. Just having mounts on my bikes allows me to quickly move the bag from bike to bike.
My Lezyne multi-tool, battery pump tire levels and extra plugs all fit nicely in this saddle bag. The side straps hold it super secure under the seat, however the seat post loop is too big so doesn't grab much of the Velcro. Thankfully less important and I have twisted the non-Velcro side to make it shorter. The bag uses a very protective material. The zipper has a nice pull loop but worry about the zipper threads getting dirty and stop freely sliding. A little larger zipper may alleviate this potential.
I have two of these: one for the road bike and one for the mountain bike. The bag is big enough to stuff a tube, two 20g cartridges, an inflator, two tire levers, some spare quick links and a multi-tool in it. On the mountain bike, the tube comes out and I carry a tubeless plug tool. The bag snugs up nicely under the seat. .The only slightly dificiencies are: no hook for a rear light, and the zipper does not go back far enough on the sides. That doesn't limit functionality. I lke this bag, alot, and it comes in multiple colors, if that's your thing.
I'll start off by saying I've never been able to figure out how the light mount is supposed to work, even after emailing Restrap and getting a vague response back. That doesn't detract from the rest of the bag. Big enough to stuff a rain coat, snacks, and a bar mount headlight inside for a long afternoon ride. No problems with it flopping about, and construction feels solid. Haven't tested it out in the wet, but if it's like my other Restrap bags, it should keep everything inside nice and dry.
