I be so very happy I buy this for my son . I dress my little on in footsy pj 's , but be always worry about he be cold because I would often forget to cover he with a blanket . I would always have to go in after he be asleep or he would roll onto it . since I have to wait I would usually fall asleep . now I do not have to worry . I get it for my 16 month old son who be pretty tall . -lrb- guess 31ish inch at the time -rrb- the large fit perfectly . it keep he warm and allow he to still stand and move . I would not let he run in it though . : -rrb-