This 4"x6" acrylic plate is 1mm thick and includes small circles ranging from 20mm to 65mm to use for pressing clay to create studs to the exact size you desire every time.  Watch my igtv for how to use them. These are great for rolling out coils and making beads too.   If you have two, you can also use one on each side of the clay as guides to get to that small 1mm depth.  (If you purchase two, I will include a free acrylic roller at no cost.)