I like these A LOT. They are very soft, and the elastic bands seem to be of a high quality. We have only had them a couple of weeks so far, but they seem durable. My son is almost 5 years old. He is around 47 lbs and 46 inches tall, but he has a big bottom. I bought these in a size 6/8, and they fit great right now. Based on the fit, though, I think he will outgrow them if he gains a few pounds. So I might suggest buying up if your little one has a well endowed behind.

These undies are vivid colors, and very nice quality in terms of thickness and stitching. They fit as expected in terms of size, but be advised they come very high on the torso, in part because of a wider than normal waist band. My son is short so this made them bunch up a bit as they sat at his natural waist, but he seems to think they are just fine so I let it be.
The only reason I deducted one star was because of the horrible smell they came with. I am usually the mom who rolls her eyes at the hysteria a lot of people display concerning any faint odor from new clothes, but this time it really was BAD. They were clearly saturated with some sort of chemical. It took literally three washings for the smell to wear off enough that I felt comfortable giving them to him (although on the other hand, they got very soft! Color faded a fraction, but not enough to really change the look). If you wash these a couple of times before giving them to your child, it should be ok. But I have never experienced any new clothes smell this bad.

My son outgrew the size 4 character undies but the 6 were too large. I think the Trimfit smalls fit like a size 5. Great for skinny guys with tough to fit waists or in-between sizes. My son says they are comfortable. Don't get the fuss over the paper tags. I ripped mine out no problem. Soft material. Washed well. Will purchase more.

These are so great! I have twin three year old boys with teeny little butts. We just started potty training and I was worried I wouldn't find any undies that would stay up on their bottoms. I read the reviews on trimfit and decide to give them a try. Yay! They're perfect. My boys wear 18 month shorts (and 3T-4T shirts, they aren't munchkins). I fear for winter since 18 month pants are waaaaay too short. Anyway. Not the point. If you have relatively normal sized boys with skinny butts, these underpants will work for you! At least the XS will for three year olds! Super soft and well made too.

These underwears are perfect! The cut and colors. We've been looking for underwears like this for our 3 year old toddler. We've gotten ones which were too tight in the thighs for my little one as his legs are normal to thick and they were very uncomfortable for him, but these are the perfect cut, it does't lay on his thighs at all and my little one is happy so now I'm happy! We got the 3t/4t size. They're slightly bigger so there's room to grow into. My little one just turned 3 in May 2017.