ironton anti-fatigue puzzle mats - 4-pk. ironton these ironton anti-fatigue puzzle mats are great cushioning for your feet or knees as you work on time-consuming projects. made of ethylene-vinyl acetate rubber (eva), these mats are water-resistant, easy to clean and lightweight. pack includes four 24in. x 24in. panels in diamond-plate pattern and 8 borders. panels can be interlocked to create the mat size you need.