63 MM Herb Grinder 4 Part with Screen . These assorted Color Metal Herb Grinders havea built-in pollen catcher screen that offer a perfect way to prepare your herb. Diamond teeth effortlessly reduce raw material to fine grain. If you’re on the go, you can trust that the magnetic closure of this metal grinder will keep its contents secure. The exterior of this rugged metal herb grinder is painted with bold explosions of color.