Easi-Grid master plating device 

Essential tool for master plate making. Holds any 90-100 mm petri dish firmly in place above any of nine popular grid patterns for molecular biology, genetics, and microbiology applications. Grids are printed on clear acrylic, so they can be used on benchtop or light box. Patterns include 25, 50, 70, 100, 150, and 200 squares; 6 and 12 circle segments; a black 100-square grid; and a blank for custom grid design.