Ammonia Checker® HC Reagents (25 Tests),JIABEN FA2-6E-1106E Trigger Switch 6(6)A 250VAC 5E4 with 2 Wires,HI774-25 Hanna Instruments Phosphate Ultra Low Range Checker HC Reagents (2 Set - 50 Tests),JIABEN FA2-6E-1106E Trigger Switch 6(6)A 250VAC 5E4 with 2 Wires,Hanna HI713-25 Phosphate Meter Checker Reagents, HI 713-25 for Phosphate Checker HI713 - Presented by Magnum Media