As per the data mentioned over the pack, a single time application of the roll on must stay good & repel mosquitoes for around 8 hours however in my view depending upon humid or dry environment ,inside or outside, sun or shade practically It is good for just 5-6 hours which is decent enough.
It needs to be gently applied on the kid clothes before going out both on front, back of shirt and pants. It is good but not too much effective if too many mosquitoes. We find it good for our kid use. Worth trying.