I can't remember what ours are. Some electronic thing. Salter maybe?
The buttons are badly designed, with the on/tare and metric/firkin-furlong-fortnight-farenheit units functions on different corners of the same button, so I keep having to start again in metric. I had to replace one of the tactile switches a couple of years ago, after getting bored of removing and re-fitting the battery in order to boot it up. I won't hold that against it, though, as tactile switches aren't known for their reliability, and are easy to replace.
Works fine on baking ingredients, bicycle parts and sufficiently cooperative kittens.