Yes, it is called a "Ruby Beholder" or something like that. I have 2 of them, I think. The first one I bought was of cardboard frame with a plastic wrap type center. I lost that one around here somewhere and bought another at JoAnn's with a 40% coupon that is a red hard plastic. They are great for figuring the value. You'd be surprised sometimes at how dark or light a fabric places against something that you thought was either darker or lighter.
You can also take a photo of the fabrics and print it up "grayscale" on your printer.