Can anyone tell what this is under the hood?

[Tester]

We use this in a pole barn where all kinds of vehicles are stored.

https://www.menards.com/main/outdoors/insect-pest-control/animal-traps-repellents/messinas-reg-rodent-stopper-reg-ready-to-use-repellent-spray-32-oz/rs-u-016/p-1444439512206.htm

Haven’t seen hide nor hair of any critters.

Tester