Both these were bought in a sale, I can never resist a bargain.
I used to use this when foundation piecing, right next to my sewing machine with a small rotary cutting mat to one side. (You can tell I'm English by all the tea stains on it)
I bought it originally to take to class, but I don't do classes any more. It used to have a handle on the end but I cut it off to fit it in my portfolio bag.
I would still use this for larger foundation units.
This little Omnigrid one is perfect for what I'm doing at the moment. Now I know how useful it is, I would have happily paid full price.
Just open it out and there you have a small cutting mat and ironing surface.
One of the least favourable bits about foundation piecing is the wastage.