I have a number of packs that the industry refers to as Day Packs. These are seemingly lightweight, 20-30L volume, and frameless. The other features are optional:sternum strapshoulder pocketsside pocketsback pocketunder pocketstraps vs vestpackablesnapsand so on…The packs under consideration…G4FreeUltimate DirectionKlymit StashKlymit DashMatador Freerain 24Gossamer Gear Minimalist 24Gossamer Gear QuickSak 26Sea to Summit Ultra-Sil Day PackSorensen Shadow 28Ultimate Direction 15Camelback Arete 22MarmotThis is my sample kit. It’s part emergency day hike kit and part over night. There is a hammock and ground kit including a bugnet, inflatable pad and poncho tarp. Plenty of overlap and a way to stay dry or just sit out a storm in comfort. This kit weights about 4 pounds.Sorensen Shadow (front)The Sorensen has the most outer pockets including the largest back pocket and underside pocket/ This design looks similar to the Pilante pack. The material is questionable as to whether tit’s waterproof or not. It’s some sort of woven impregnated fiber.Sorensen Shadow (back)This is the only vest in the group. The vest pockets are tight and not meant to hold a water bottle. I could barely get my phone in there and so it’s more likely best for a small knife or maybe your keys. Worst of all it does not fit my 50" chest. Also includes a thin plastic sheet to act as a stiffener.Sea to Summit (front)Probably the lightest in the bunch but it does not have any pockets. The thing is you gotta hick your own hike and in my case it means hike until you have to stop to do something else like drink or snack. About the only real downside is what to do with trekking poles if you change your style.Sea to Summit (back) There is no sternum strap and the straps are very minimalist but comfortableMatador (front)Average (read normal) side pockets for water bottles or gear. and a nice, mostly sealed, zippered pocket on the front which can be a convenient swing on one shoulder in order to access. I was able to fit a 1L and a 1.5L bottles into both side pockets.Matador (back)The straps do not lay flat on my 50" chest. At this light weight that’s not much of a problem and the sternum strap does help orient the strap at the top of the shoulder.There is talk about cottage industries in the hiking gear world and the adoption of some of those designs and ideas by the big manufacturers. The three legs of the stool seem to be quality, consistency and price. Just look at the seams of the Matador and Sea to Summit.Gossamer Gear (front) Huge side pockets and a brain this is a nice pack.Gossamer Gear (back)Gossamer Gear (front)The minimalist is my go-to pack when I go to the soccer tournaments with the kids. The straps are generous and soft. It carries my water bottles, Poncho, collapsing chair, first aid, snacks, and other misc that gets me from the car to the field. The material is super durable.Gossamer Gear (back)The extra pocket is not useful and needs to be removed. The other bottle strap does help when I’m carrying for the family and not just myself.The Marmot side pockets are misleading. They will hold a 1L bottle and there is a cinch strap to keep it in place. The brain is a good place to keep snacks and the brain strap means you can over stuff the main body. I like the color of this one because when I hike I want to draw attention to myself even though black dries faster.The Camelbak is one of the smaller packs but it still carries enough for an overnight. The pocket configuration seems to be biased toward using a hydration bladder. It’s not a terrible idea except bladders are a single point of failure and take more time to fill. Not because of volume but because you have to empty the pack to gain access.The Ultimate Direction pack is meant for skinny people. Even thought the 15 does not carry much the vest is just tiny… for a runner’s frame. I was able to squeeze into the pack and after going back for a second try I realized that the fit was just different. The pack rides higher on my shoulders and the straps were meant to wrap tighter into my armpits (but not too tight). The idea might be to get the pack higher on the shoulders.I tried the pack empty and that made a big difference. Part of the fitting had to do with the contents making the pack more ridged.Not currently pictured are the two Klymit and G4Free packs. The G4Free is functional and one that I’ve probably used the most but it’s not the lightest and it’s not waterproof at all. The Klymit packs continue to have problems staying inflated.Selecting the best day pack can be a challenge. It’s partly form and function' and partly survival. Not to over emphasize a day hike is the easiest to walk away from. In my favorite area there are 30-40 miles of intersecting trails… I would have to be trapped by fire, flood or animals not to make it out in the same day.PS: One serious problem with black packs is that they also heat the contents of the pack. I recall my Klymit pack and having room temp water in the pack and by the time I drank it… it was hot.UPDATE 2019-05-17: not everything is about weight. Sometimes it’s about volume. I took the kit above and replaced the inflatable pad with a torso length closed cell pad. While the foam pad provided structure to the pack like a frame would it had friction that made it difficult to get in and not of the day pack. If I wanted a sit pad I’d have to dump my gear. I tried a number of different sized pads and had some interesting results to be shared later.