I use the ones from Auber Instruments good value and great service. . . . Since Lurch closed down Watch Hill in the UK they tend to be a bit more expensive . . . Lurch put me on to Sterling Sensors - 0161 620 0410 an old rival that bought most of Watch Hills old stock . . . Don't forget your gland . . I use a 3mm compression to M10 female (with back nut) for mine
RS components are good.
I use these in work Platinum Resistance Thermometry. These types of sensors are more stable and accurate than Type âK. They are generally more reliable and overall better performing than the K type. hence why they are generally more expensive.