My dauthter is potty training (22 months) and winter is here, I knew I needed an undergarment but a full onesie is out of the question, so the next best thing was the camis.  I was a bit worried they about the size 2T-3T was the smallest, thought they would be too big but they weren't. They are pretty basic but very cost efficient, 5 come in one pack and they were like $5.  Not bad.  They wash well and should carry her through the winter.