Inside a couple of mosquito repellent/killer vaporisers.

These things are commonly sold in the UK for taking abroad and using in your hotel room at night to deter the risk of mosquito bites when sleeping. It's quite odd that the Raid one has a square pin plug on it.
These devices use vaporiser pads which are basically a piece of cardboard wick soaked in pyrethrins. A chemical derived from or based on a natural chemical that plants like Chrysanthemums use to protect themselves against insects. While the vapour is harmless to humans, it interferes with the nervous systems of insects.