Some clarification with some spec numbers I've found please!

Hello, 1st of all, my specs for headset/bearings list 25.4mm, (so assuming 1 1/8” for headset) and then 30mm/34mm.. is this 2 dif bearing sizes or is it listing an OD and ID? Also, my BB calls for 73mm x 122.5mm, and I'm not having luck as much searching for one, are these harder to find now days?