I'm selling my Chilipad Cube, the innovative bed cooling + heating system. It works well, purchased May 2020. You can read more about it at the link below. In short: you fill it up with water (which you have to top off every few weeks or so), and then it pulls heat from your body (or adds heat if in heating mode). When I use this I wake up cold, it's like having a cooling pad under you as you sleep.
More details: https://sleep.me/product/chilipad-cube