Rugged and reliable, the Pro20 provides everything you need in a handheld dissolved oxygen instrument. User-replaceable sensors and cables, 50 data set memory, and convenient One Touch Cal feature makes it user friendly. Mil-spec (military spec) connectors, IP-67 waterproof and rubber over molded case, and 1-meter drop tests ensure the instrument remains in your hands to provide years of sampling even in the harshest field conditions. Fast response times allow you to complete your sampling routine quickly, saving time and money.