I want to know the answer to the following question:
What replaced the UB 2?
All the background I'm provided with is that "Height finders were also increasing in size, in Britain, the World War I Barr & Stroud UB 2 (7 feet optical base) was replaced by the UB 7 (9 feet optical base) and the UB 10 (18 feet optical base, only used on static AA sites).". Is that enough to answer the question?
Answer: yes