The 5L size was better for my type of hiking. Half day hikes to carry essentials plus snack and water bottles. The 2L was just too small once the water bottle was added. Like that the 5L has room for two bottles on hot days and has a pocket in front for phone.

Exactly what I was looking for.

While this is designed as a biking pack – and fits comfortably over the lumbar area – I've gone back to my childhood hobby of rollerblading, but this time with my partner, and I wanted a pack that would be comfortable to wear but also keep me hydrated on the go. The Osprey Savu 5 is everything I need and more, and will help me work up to longer skate sessions.
The back panel is well vented, and I didn't get unreasonably sweaty in that region. I was able to move and flex comfortably, and the pack didn't impede my movement. The waistband is easy and comfortable to adjust. The main pack is generous and allowed me to stash what I needed for a moderate temperature afternoon – keys, a wallet, a phone. I'll probably add a first aid kit and a windbreaker later, and I know that this pack can hold these things while still feeling light. I can even add some electrolyte packets and snacks. I can see how this would be extremely helpful for biking, as carrying tools to do repairs on the go is extremely important. This pack holds a ton, and there is even some organization to help you keep everything accessible – several pouches with zippers, mesh, and even a key holder! There is also a zipper pouch on the front of the main compartment, although it is not very wide and is really best for thin/flat things.
There are two bottle holders, one at each side. I used 16.9 oz bottles, but will probably switch to sport bottles later. I prefer this over a hydration pack right now so that I can use electrolyte packets without having to do a deep clean of a bag. I had no issues removing, using, and replacing the bottles while on my skates. Drawstrings and mesh pockets help to keep everything secure, and I had no issues with my water bottles falling or becoming loose. There are zippered pockets on each side of the hip belt as well, but I did not have a reason to use those.
$75 seems a little steep for this product at first glance, but it really does meet the odd needs of someone who bikes/rollerblades. Osprey makes quality bags. If you've ever owned an Osprey, you know they last forever! Osprey will occasionally have their bags available at a lower price depending on season or color – if you enjoy bicycling, this is a bag to get, and anything under that price is a FANTASTIC value.

Osprey delivers another quality fanny pack. This pack looks stylish, and has very good functional design. The pack uses beautiful material, and is lightweight. It is large enough with ample compartments for water, accessories, and snacks. There are two inner zippered compartments and one additional compartment next to the main compartment which is perfect for the wallet. The water bottle holders use elastic material, and have additional strapping which are easy to tighten and loosen. Zippers work smoothly, and zipper loops make it easier to work the zippers. The belt compartments have gathers which increases the volume of the pockets. The strap above the main compartment makes it easier to hand carry the pack when loaded up, and is also a good way to hang the fanny pack. Designed for the way we use packs.

I didn't like the white interior and white zipper pulls. The camo pattern is faint and it looks just kinda brown.

I got this waist pack to carry small essentials without wearing a full backpack, and it’s been a comfortable option for shorter bike rides and daily dog walking in the summer. It sits securely around the waist and doesn’t bounce around much once adjusted properly. I like that it keeps items like keys, treats, and small supplies within easy reach instead of digging through a larger bag.
The bottle pockets are a useful feature, especially for carrying water during warmer weather. They make it easy to stay hydrated without needing a full backpack, which is great when walking the dog on hot days. The storage space is enough for basic essentials, though it’s not meant for carrying bulky items. The material feels durable, and the zippers move smoothly without snagging.
It did take a little time to get the straps adjusted so it sat comfortably, but once dialed in it stayed put and felt balanced. For everyday activities like dog walking or shorter outdoor outings, this has been a practical and comfortable option to use, especially during the summer months.