75 watt and will heat up to 50 litres if the container is lagged.
Pre-set to 24 C , adjustable so you can tweak it up or down if you want.
We like to turn them down to about 23 C
It's suitable for a demijohn or a 5 gall fermenter. There's a rubber bung attached to the cable with a hole to take an airlock so it seals the neck of the fermenter and you can still fit the airlock.
You can use these in a garage with no heating, as long as you lag the fermenting vessel, use a sleeping bag or a duvet. In a heated house there's no problem.