I originally bought the smaller version of this bottle but returned it and purchased the larger set. The smaller one is more the size of your standard, disposable plastic bottle of water you would buy by the case. The larger one still fits in my car’s cup holder, but I don’t have to refill it as frequently. I bought these because I wanted a glass bottle with a lid that wouldn’t fail, leach toxins, or develop mold like all the plastic and metal options out there. The bottle and lid are both glass so obviously they are likely to break if dropped on the ground, but I have managed to be careful enough so far to keep that from happening. I do not think the glass is overly thin. It’s much thicker than a lot of my drinking glasses. I use this bottle daily and take it with me to soccer games and running errands. There is a silicone (not plastic) seal on the glass cork so that it will maintain a waterproof seal and prevent leaks. The neck of the bottle is very narrow so you’ll need to buy a water bottle scrub brush to keep the inside of the bottle clean, though this set comes with one; it is cheap and flimsy and I immediately threw it away. I have a brush that I used for years for my sigg bottles and it works great. I don’t think the insulated sleeve has any effect on keeping the liquid cold, but I mostly use it to protect the glass from breaking if I’m not paying attention or in a hurry and set it down on the counter a bit too hard. So, if you want your drink to stay cold for a long time, this is probably not the bottle for you. If you want to get away from plastic or aluminum and don’t care as much about your beverage being chilled, then this will fit the bill just fine.I loved the water bottle one and gave one to my supervisor but she put it in the dishwasher and it burned, so don’t do that I guess ?I always look for eco friendly options. I found a glass bottle but had a wooden cap. I loved it but it got moldy pretty quickly. This bottle is really pretty and is all glass which makes it fragile but at the same time I know it will not get moldy. I highly recommend this bottle!!!It's a nice glass bottle for the price and size. Those black markings on the cap just happened to be on BOTH of my original order and exchange reorder. Found out the sphere ice cubes I have doesn't fit through as well. Will be returning and purchasing elsewhere.I am very picky about my water bottles. This one is a good one and it came with two which is a bonus. It’s small enough to fit in a purse and car cup holder. I went with the smaller size so I could easily keep it in my purse. I like the time chart on the side to remind you to drink. The cover is helpful especially when traveling with this glass bottle. However it doesn’t keep the water cold it’s more just a protection. The lip is small enough to chug water without getting it all over and the lid fits well and doesn’t come off easily.It's pretty nice! Very obviously Chinese made, the manual/cleaning guide is in Chinese with English translations below. I got the smaller one and it's a good size to hold, not too small or too big. The cork is remarkably strong, it has four different fins to keep water inside, though it also means it's hard to just pop open. I 100% don't believe it's borosilicate glass though. The sponge brush they give you for cleaning is a bit of a joke though. It doesn't reach to the bottom at all and it's basically a bad sponge on a stick, so you'll probably want to toss it immediately. Overall not bad especially since it gives you two of them.I wanted to get away from plastic water bottles. This is perfect. The only bit of plastic is for the seal. Many other glass water bottles have plastic spouts or caps and I didn’t want that. This is great because it is mostly glass. It’s exactly what I was looking for. It feels durable and looks amazing.Bottles are great but brush is like 3” short. Not sure why they included a tiny super skinny brush that can’t reach the bottom of the bottle!!