This red, round pill imprinted with B 30 is a 24 HR Nifedipine 30 MG Extended Release Tablet [Nifedical], per the NIH.
Nifedical is a human prescription drug. The active pharmaceutical ingredient is nifedipine and is classified as, "Calcium Channel Antagonists [MoA], Dihydropyridine Calcium Channel Blocker [EPC], Dihydropyridines [Chemical/Ingredient]."
This pill is made by a total of 2 firms: (1) Teva Pharmaceuticals USA Inc, and (2) Bryant Ranch Prepack.
There is 1 other red pill that with a similar imprint: "B 30". They may be a different dosage of the same drug or a different drug entirely.