A 100 mm dia lens covers the entire illumination field magnifications assure highly accurate results. Counting plate with standard Wolfhugel ruling ensures clearly differentiated and sharply defined colonies. This model is fitted with automatic 4 digital Display. Each touch of marking Pencil on the Petridis increments the colony count by 1 and the glowing L.E.D Maximum colony count possible up to 9999. Suitable to work on 220V, single phase, 50Hz, AC supply.