Wall / duct holder (for Mounted duct probe in duct or on wall)$42.00 For 6621, 6651, 6681, 6682 Call us for a quote Product Model: 0554 6651 Wall / duct holder (for Mounted duct probe in duct or on wall) quantity Add to cart SKU: 0554 6651 Category: Testo Sensors Parts & Accessories Tag: Testo Sensors Parts & Accessories Description Description For 6621, 6651, 6681, 6682 Related products Testo 340 NO Replacement Sensor (Low Range) (0-300 ppm)0 out of 5 $835.00 Add to cart Self service replacement CO measuring sensor – 325-1 & 325-3 only0 out of 5 $219.00 Add to cart TC with tube and plug NiCr-Ni0 out of 5 $366.00 Add to cart