A systemic gram positive ring device suited towards Gram Positive organisms carrying 8 antibiotic impregnated tips allowing the simultaneous application of the equivalent individual antimicrobial susceptibility test discs.A paper ring 65mm in diameter with eight projecting arms. Each arm is impregnated with a different antibiotic identified using a letter from the key.Pack Size - Pack of 50 Mast RingsAntibiotics include:Chloramphenicol - 25µgErythromycin - 5µgFusidic Acid - 10µgOxacillin - 10µgNovobiocin - 5µgPenicillin G - 1 unitStreptomycin - 10µgTetracycline - 25µgAlso available as a pack of 10 Mast Rings (B8A18715)