Stainless Steel Sensor Fitting. We supply an array of stainless steel fittings & unions complete with nut & olive which are used to connect sensors to thermo pockets, thermowells or direct into the process. Some sizes generally in stock are 1/8"bsp 1.5mm & 3mm. 1/4"bsp 3mm & 6mm. 1/2"bsp 6mm