A systemic gram negative ring device suited towards Gram Negative organisms carrying 8 antibiotic impregnated tips allowing the simultaneous application of the equivalent individual anti-microbal 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 100 Mast RingsAntibiotics include:Ampicillin 10µgCephalothin 5µgColistin Sulphate 25µgGentamicin 10µgStreptomycin 10µgSulphatriad 200µgTetracycline 25µgCortrimoxazole 25µg