165H Cats comparison. The glaze on the left is sky blue, the one on the right is clay blue. Confusingly, both pieces are the small 3" size. The sky blue cat is from about 1942 while the clay blue one is from 1953, the last year of Ada clay and the first year of clay blue. From 1950 until about 1952 the cats were larger, 3 1/4" in height.