First of all, these are fairly decent paint cups. I was somewhat concerned after reading some of the other reviews regarding these cups that they would be too big, but was pleasantly surprised once they arrived. They are ~4" high (including top hinge), with a bottom diameter of ~2 ½", and a top diameter of ~3 1/16 (or ~3 ¼ if you include the thumb-opening). They have a fill line ~1 ¼ from the bottom which is the maximum it is recommended to fill these in order to prevent accidental spills. The lid snaps shut reasonably securely, and flips opens almost 270 degrees (250 perhaps?) and so will not fall closed while in use. The lid also has two sets of ridges on it that can be used to balance a paintbrush across in your choice of two different angles. In use I have found these a good size as they are small enough that my young son can easily maneuver them, and yet big enough that they don't easily tip. I also chose to only fill them under ½" for three reasons: (1) limits waste if my son accidentally mixes colors by putting a dirty paintbrush in the wrong cup, (2) prevents my son from dipping the paintbrushes too far and getting paint on the handles, and (3) will hopefully allow him to use the paint fast enough to prevent it from drying out. I should also mention that my 3 year old son has no problem opening or closing these containers. The reason I docked these cups has mostly to do with quality. While these seem sturdy enough, it was somewhat frustrating to put the lids on as they only have a single thread and it was tedious to try and get them on straight. These are obviously also not airtight by any means (no rubber seals, etc). For the price that is not unexpected, but would have been nice to not have to worry about the paint drying up if my son takes a week off from using them. These are also, as expected, made in China. I should also mention that they arrived stacked together very tightly (perhaps due to the heat during transport?) and were difficult to separate. On a side note, it would be nice if there were better options out there (ie. airtight, good quality, etc). While other brands are likely better quality, they tended to be available only in sets of 4 for primary colors (plus green). These were the best, no-spill option I could find that offered a good selection of colors and yet I am somewhat disappointed that no one makes a slightly larger set (anyone notice how there is no pink?). Naturally, I could (and eventually will) teach my son how to just mix these colors on the side, but, at my son's current age, that would be far too messy. I have noticed that Amazon now offers the individual cups for sale and so I may eventually pick up a few of the white ones and mix the other colors for him (pink, gray, and perhaps sky blue with how appealing outdoor scenes normally are for kids), but it would be nice if matching cups were available.