Kids skis come in two varieties, Carving/Race Skis and Twin Tips. Carving skis are best for kids just starting out and doing general all mountain type skiing. Twin Tips are better for adventurous kids getting into hitting jumps and can be better for kids who travel as they are a bit better in Powder.
With kids skis it's important to go for a narrow ski. Kids, being shorter, don't have the same amount of leverage over a ski to get it on edge.
Kids Carving & Race skis range from 60-70mm which is great for kids progressing.
Kids Twin Tips are often wider, which is fine if they are stronger skiers, but can really inhibit progression in kids who are just starting out. Really strong kids can typically handle skis up to 90mm in ~150cm length, but limiting width to 85mm is better for All Mountain performance.
|Kids Ski Length Guide||Kids Height|
|Skier Ability||Beginner||Subtract 25cm|
Kids ski length depends on both Height & Weight, so if between sizes, size down if they are lightweight and size up if they are on the heavier side.
Parents if you are looking to get a couple years out of kids skis it better to size them correctly for year 1 and then short on year 2 rather than size up and have them be too long initially. Kids on skis that are too long can really struggle to improve.