Robuta

https://www.cngoodfitting.com/stainless-steel-bsp-bspt-thread-fitting/
There are 2 types of BSP threads: BSPT (British Standard Pipe Thread) and BSPP (British Standard Parallel Pipe). They both have a thread angle of 55°, BSPT is...
stainless steelbspthreadfitting
https://www.detroitnippleworks.com/bspt-nipples/
An informational page on British Standard Pipe Thread Nipples or BSPT Nipples and how they are used.
british standard pipebsptnipplesthread