M4 thread. Take care to not over-tighten when replacing.The threads on this thermostat do not (and usually will not) need to thread all the way into their associated part. If you try to thread it in all the way flush with the part, you run the risk if the stem snapping off, so do not attempt it. Hand-tight is sufficient.
Thermal paste (or “grease”) aids heat transfer between the switch and contact surface by filling in microscopic imperfections in the metal surfaces. It is especially useful for pipe mount applications.
A key characteristic of this synthetic thermal grease is it’s long-term material stability. That means it won’t harden, dry out, or melt in normal industrial use.
Smear some paste on the sensing head of the thermostat switch prior to bolting or clamping down. (Not to be used as a glue.)
WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.