Spark Plug query

After a wee clear up of one small section of my garage, I found a Bosch Spark Plug.
Whoopee - no surprises there! But despite sharing the same size and thread of yer typical W8AC model (as used on most Type 1 engines) it was an unused W145T1 model with ‘Cr-Elektrode’ (Chromium), and obviously very old judging by the state of it’s wee cardboard box. Probably inherited from my Dad’s old Bug spares from the 70’s around the time we moved to the village 13 years ago.
So, er, anoraks on - what kind of heat rating & power of engine were these made for? :think
If there’s any advantage for a tuned engine that runs a bit hotter, I’ve just got to find another three… :mellow:

yes they are the same see
http://www.type2.com/library/electrip/sparkpl.htm