Duct probe -30 to 120°C$299.00 For Testo 6651. Call for changes in filter, cable and probe Call us for a quote Product Model: 0555 6603 Duct probe -30 to 120°C quantity Add to cart SKU: 0555 6603 Category: Testo Sensors Parts & Accessories Tag: Testo Sensors Parts & Accessories Description Description For Testo 6651. Call for changes in filter, cable and probe Related products Self service replacement O2 sensor – 305/325M & XL0 out of 5 $90.00 Add to cart SO2 replacement sensor (0-5000 ppm 1 ppm resolution)0 out of 5 $525.00 Add to cart CO2 replacement sensor kit with board0 out of 5 Read more