Features Include:

• Integral (i.e. built-in) cable with 1- 4- 10-m field cable; user-replaceable DO sensors
• One Touch Cal allows for easy DO calibrations within 3 seconds with the press of a button. Automatic barometric pressure compensation.
• Quick response times; 95% response time in approximately 8 seconds with standard membrane (fastest response time on the market)
• Stores 50 data sets; no need to write down data
• Large graphic, backlit display and glow in the dark keypad
• A true field instrument - the display is visible when wearing polarized sunglasses
• Tough. IP-67, impact-resistant, waterproof case. Waterproof with and without the battery cover
• Rubber over molded case provides extra durability
• Multiple languages: English, Spanish, French, and German
• 3-year instrument; 2-year integral cable; 1-year polarographic sensors; 6-month galvanic sensor warranty

The Pro20i features an integral cable, but the Pro20 features a user-replaceable (i.e. detachable) cable. Longer cables are also available for the Pro20, as is a BOD probe/cable assembly.