The S-187(*)/MRR-8 is the shelter for the Receiving Set, Radio, Shelter) AN/MRR-8. It is a modified S-141/G shelter. Known are the types S-187/MRR-8, S-187A/MRR-8, S-187B/MRR-8 and S-187C/MRR-8.
This is the S-187C/MRR-8: