I'm very happy with this set of travel bottles. I previously ordered a different type that had a firmer plastic bottle that seemed more suited for thinner liquids like a light soap or shampoo. I mainly get these for sunscreen, and those often are a thicker type of viscous lotion. The previous set I had were very difficult to dispense out of since the bottle was harder to squeeze and apply even pressure for getting the lotion out of. These bottles on the other hand are great! They're a soft silicone material that are soft touch, and the lid design is also excellent since it has a membrane layer at the actual opening to prevent accidental leakage, and the membrane poofs open when you squeeze the bottle with enough pressure making it very easy to dispense a controlled amount of lotion. I've tested it with a thick mineral based sunscreen from Blue Lizard and it works great. Also tested squeezing the bottle with the cap closed, and it feels very airtight so I'm confident it won't leak even with the pressure change on the airplane. The bottle material is also stretchy and flexible so it should withstand the stresses of being expanded and contracted. The colors included with the set are very nice, a soft pastel blend variety so it would actually be a good visual differentiator between different lotions since the bottles are opaque and not easy to see what's inside. That could be the only downside of this type of bottle but there is also an included set of labels covering all the different essentials one might carry in these bottles, which could easily stick on the rim of the lid. I also appreciated the inclusion of the clear zipper bag which perfectly fits all 4 bottles making it great for organization in a travel pack. Overall highly recommend this set of travel bottles for anyone needing to bring just the right quantity of liquids to get through TSA with a carry-on bag.