⭕ Environics S-9100. This is a top of the line gas calibration instrument. Single owner. Unit is less than 14 months old. In excellent cosmetic shape and perfect working order. Available for shipping or collection. This unit is equipped with both ozonator and 2 - RS 232 communication ports options. The Series 9100 consists of a single chassis supporting up to 3 thermal mass flow controllers, an ozone generation module, a mixing zone, a reaction chamber for gas phase titration, and control electronics.