Where do people buy pneumatic testing equipment?

Am curious where do people source academic/research quality probes/sensors/etc. such as pressure or temperature sensors? The sort of stuff that has really good accuracy and sampling rates counter to what may be found in other settings like industrial or commercial. As specific example, the ISO 6358 spec defines a stainless steel pressure measuring tube with certain dimensions on port holes...where would you even get something like this?

Are there well known brands of pneumatic testing equipment or online sites anyone can share?