Pt100s and Pt1000s are two types of temperature probes (temperature sensors).
They are both platinum resistance thermometers (hence the ‘Pt’), as opposed to thermocouples.
The main difference between Pt100s and Pt1000s in general is the electrical resistance at 0⁰C, which is the number in the name: a Pt100 is 100Ω at 0⁰C and a Pt1000 is 1000Ω at ⁰C. This makes Pt1000s more accurate for small temperature changes as they would result in larger changes in resistance when compared to Pt100s.
In the context of standard Radleys equipment, Pt100s are the external temperature probes you plug into circulators (such as a Huber Unistat), typically to measure the temperature of the contents of a reaction vessel (e.g. in Reactor-Ready). Our jacketed lab reactor vessel kits all contain a Pt100 of an appropriate length. These Pt100 probes are PTFE-encapsulated, for excellent chemical resistance. They use a LEMO connection as shown below.
Again considering typical Radleys products, Pt1000s are the external temperature probes you can plug into a hotplate, and then insert into a probe hole in a Heat-On, Carousel base or StarFish Mono/PolyBlock, or alternatively into a flask. All our current stirring hotplates are compatible with a Pt1000. The standard Pt1000 material is stainless steel, but glass-coated sensors are also available for if the Pt1000 will come into contact with chemicals that corrode stainless steel.