Topeak Aero Wedge Bike Saddle Bag with Velcro Strap - Waterproof Cycling Storage for Tools, Phone & Essentials - Perfect for Road, Mountain & Commuter Bikes

This is a quality bike - under seat bag. The only reason I gave it 4 stars is that the attachment for the seat post was much too big. When pulled tight around the post it was past the velcro attachment. It was easily fixed with some simple stitches but I could not see how others did not find it loose on the seat post. Also, please realize that these are fairly small. I got the medium size which is perfect for a cell phone and a few small items. I would think that the small size may not hold many larger phones.I bought the medium sized bag. It fits nicely. In hindsight, I wish I bought the large one.Perfect size for my phone tube and a multi tool. Easy to install and just what I needed.It offers everything the product says it offers. But I thought it was smaller according the pictures. Went for the medium size just to be safe. Huge saddle bag. I think the micro would have also fall into that category. I think. The mounting system is quite easy with velcro strips. Would have loved to see something more robust. i am currently checking some other small options from the same company. I'm not giving it a bad calcification because in the end it describes everything it offers. Just keep in mind the size is huge for me.This bag is a size large. Photos show bag size as it is before you open the zipper to make it larger. I go on long rides (50-100 miles) and this really holds a lot. I have a travel pump, CO2 cartridges, patch kit, tools, tubes and still have room for more. It is easy to remove as well, so I can easily change it over to my other bike. Sturdy with a strong zipper. Highly recommend.I bought one of these a couple years back and then again recently when another brand finally died. The material and zippers are bulletproof in my experience and it is really solid.Downside is that you have to undo at least one clip to open it and even with the expansion zipper open it feels small due to the horn shape. It’s very narrow in the front. I got the medium size. Small might hold your keys. Medium holds a tube, basic multi tool and my co2 stuff. Little net on the door is nice for holding ID or whatever.Zipper is not weatherproof. So plan to ziplock bag anything that can’t get wet. I would rather do this than replace a waterproof zipper every couple years.Still, as I said, I bought it again. Good, small bag.I had difficulty deciding between this Topeak seat bag and the Bought the medium. Holds a 27" mountain bike tube and a couple of tire irons and some patches perfectly with a little room to spare. Solid attachment to standard seat rails. Even has a spot to put a small tail light on it.So I received my medium saddle bag and having worried about size I was more surprised how big it is. I have a photo what I keep in it without opening the extending zip granted a tight squeeze but the squeeze does stop any rattling. Inside it has some mesh to stop tightly packed kit falling out in the lid. It also has 2 elastic strands on the outside if you want to hold something small. On the outside lid is a tab as shown in the photo below the silver line where you could attach a rear light. My only down side is it is definitely not waterproof as when held up to the light it's possible to see light coming through I got round it by using a dry bag as shown. So far I think it is a great product and you can carry everything you need to get you out a jam and some extra luxuries. I will come back to this when I have some proper use out of it.I tried this out on a 150k bike ride and found I could fit most of my essential tools in - as well as an Indian snack selection - but it rubbed against my thighs, which felt uncomfortable and produced unpleasant creaking noises (which weren't related to my consumption of the Indian snack selection). When I tried pushing it further up my seat post, it swayed from side to side and produced even more weird noises (also unrelated to the snack selection). The medium one of these is the perfect toolbag for longer rides, I'll stick with that in future. This means I may have to forego the Indian snack selection, but riders behind me will be happier.Like many others, I hesitated pre-purchase on whether to get the small or medium size.I opted on the medium after looking at measurements with a tape measure on my bike to visualise.When it arrived, I cursed initially feeling sure that I'd been sent the small version instead.But I was wrong, the label clearly showed it *was* the medium.So I just expected bigger.... it's OK, and looks neat, but thought someone wrote you could fit a small handpump in, and I had one that was probably 8-9" long, but wouldn't fit even if the bag was extended.I'm pleased I got it, but this just shows how much better it is to see/feel a product in your hands, in store, or in a picture compared to something of a known size, to better visualise the right size expected.As someone else noted, when attached snugly to the saddle underside, it's not super-easy to operate the zip to open.I was looking for a tiny bag to stash my multitool with quick slime patches and this is it. Can potentially have a spare tube there but would have space for much more. I have a hardtail MTB bike and I keep my pump underneath my bottle cage and I use slime tubes so really don't need a spare tube. In emergency, if the hole is too big and slime won't work I will be able to fix it there and then. Great.The bag fits nicely as on the photos I uploaded and tucks in nicely under the tiny saddle that I've got. Happy!I've had this saddle bag since September, and the strap that holds it secure to the seat post has torn clean off, mid ride. This is the second Topeak saddle bag I've had fail inside 12 months. I also had a medium where the stitching on the straps that hold it to the rails was coming off, I chucked that as I didn't want to chance it coming away completely in the middle of a ride with no way to secure it.I've liked Topeak's products in the past but it seems I can no longer rely on them and will be looking elsewhere for a replacement.