It can be used on different sized slow cookers as well. The white slow cooker above is a 3 Quart Slow Cooker. The one below is a 7 Quart Slow Cooker.
You can find out more about Lid Pockets on their website. You can also find them easily on Facebook.
*Disclaimer: I was given a Lid Pocket to try out in exchange for an honest review. All thoughts expressed here are entirely my own and may differ from others'.