Great solution for under cabinet heat vent. This is a nice pre-made solution to re-direct your heat/cooling register through your toe kick. Easy to use. This solved an issue for me as my heat register happened to be directly under my pull out garbage cabinet, so this keeps my garbage from cooking while the heat is on.
https://www.amazon.com/Toe-Ductor-Cabinet-Ducting-Kit/dp/B00CMXXL22