Beating China and Japan is a big deal and shows the trust of the international scientific community on Pakistan's R&D capabilities both in terms of human resource and facilities to design and manufacture such an important and precision parts for the most advanced scientific laboratory created by the mankind.
Now let me provide you guys a brief introduction to RPC which stands for Resistive Plate Chamber. RPCs are used for detecting Muon: a particle like electron with -1e charge and 1/2 spin but with a very high mass. Hence these RPCs are designed and manufactured to very exacting details and require a very deep understanding of the particle physics and material sciences in addition to precision engineering. At LHC, the sizes does matter and everything is humongous so making something that is huge in size but still very precise down to the minute details, shows the prowess of the R&D team and facilities.
@Slav Defence, sir I guess you would relish this news