Hullo KBIO....
This image appears similar to a high pressure 3-way oil hydraulic ball valve ...3-way ball valves are also marketed for low pressure applications for Water-Oil-Gas [the body has the letters in the casting ....[WOG] to represent and confirm suitabity for application
They rely on a hard chrome plated/ground/polished brass ball, and 4 x preloaded contoured POM seats
The valve body is usually externally nickle plated cast brass body
Sizings of 3-way LP ball valves are available in 1/2", 3/8" and 1/4" BSP are common and for less than $US15.00..........and from your Local Plumbing or Hardware store
I have seen an American manufactured product down to 10#32 tapered thread port size [about 3mm thread] however they were some $US320.00 each ....these were designed for Instrument applications with inert gases and liquid nitrogen etc in mind
Sometimes, a T Tube union & and additional tube needle or globe valve to dump the pressure could be a cheap alternative, or if a simple application.... a boiler water gauge blowdown valve?
Best wishes for 2021...........Derek