These antibiotic sensitivity discs are supplied in cartridges of 50. To transfer to an agar plate simply use a sterile pair of forceps. The cartridges have a long shelf life when correctly stored in a refrigerator at 4°C.Antibiotic: Penicillin GConcentration: 10 unitsPack of 50 discsPlease Note: Nutrient Agar Plates and ejector are not included.