This Oxygen Reduction Potential Meter is the must have accessory in your fight against Covid-19! ORP reading of HOCL determines its efficacy in eliminating virus particles. This easy to use meter helps you quickly and conveniently measure the ORP of Hypochlorous Acid (or other disinfectant liquids) you are using. Measurement Range -1999 ~ +1999 mv https://www.ppe-mart.com/product/orp-meter-1999-1999-mv-range/