Wall probe -20 to 70°C$275.00 For Testo 6651. Call for changes in filter, cable and probe Call us for a quote Product Model: 0555 6601 Wall probe -20 to 70°C quantity Add to cart SKU: 0555 6601 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 Testo 350XL/335 CO replacement sensor (0-10000 ppm H2 compensated)0 out of 5 $1,264.00 Add to cart 10.5′ with 13′ stainless braided TC lead 8 pin connector0 out of 5 $420.00 Add to cart Self service replacement CO measuring sensor – 325-1 & 325-3 only0 out of 5 $219.00 Add to cart