Sterile Lazy-L-Spreaders™ feature a L-shaped design for convenient spreading – turn the petri dish 360o to provide a smooth and even distribution. A smooth spreading surface with a slight upward return reduces the likelihood that the spreader will dig into the agar. Polystyrene. Individual spreader is 5 3/4”/145 mm high with a 1 1/4”/ 32 mm long spreading surface.