supply of standard calibration gasstandard calibration gas,standard calibration gas canister for dga consisting of methane, ethane,ethy lene, acetylene, hydrogen each 1000 ppm, co and co2 each 5000 ppm and nitrogen balance-0 1 no, each gases 500 ppm - 01 no, each gases 100 ppm -01 no, with septa and knob arrangement to draw sample directly from canister using gc syringe, preparation tolera nce+/- 20 percent and shelf life 12 months. canister capacity 0.5 litres, filling pressure 20 kg/sq.cm with test certificate and suitable septum as spares. [ warranty period: 12 months af ter the date of delivery ] ] => limited