We have one that is a seperate pan with a hot plate that you sit it on.
It's great as it means you can use the pan as a normal pan on the stove top or in the oven, or as part of the slow cooker and no additional pots to wash.
I find it great to start off a curry, chilli or stew around lunchtime, on the stove top, then let it simmer away in the slow cooker during the afternoon adding some veg in later on.
Works a treat.
Mind you if I get a job that means I don't work from home that ain't gonna happen nop more. No chance I'll be doing that around breakfast time!