Can anyone help me find what I need: I want to use some essential oil fragrance in my classroom in work (secondary school). I'm wary of having anything with water in, and anything that can be knocked over easily (like reed diffusers) in a busy room with classes coming in and out 6 times a day! I'm also part time so other people use the room I teach in on my days off, so I can't always guarantee it will be looked after. I have used a basic electric plug in one in the past (type you get in supermarkets) but I find their fragrances are too chemical and sickly. I love Neom and Neils Yard scents and I'm willing to pay up to £40 to make the classroom feel more calm! Ideally I think a plug in at the wall type device that you can add your own oil into would be what I'm after, does such a thing exist?