HVAC systems, residential minisplit air conditioners, package units and split systems, Class 1, Division 1 and 2, Groups C and D hazardous area rated A/C, 100 to 5000 CFMS Class 1, Division 1 and 2, Groups C and D pressurization systems, MERV, HEPA and chemical filter media air filtration systems, toxic and combustible gas detectors, instrumentation, fire mitigation systems, smoke detection systems, high and medium voltage electrical materials.