For the Printer TS207/TS307/MG2577s/MG3070s/TS3470/TR4670 have 3 options of ink cartridge

Black – PG-745s / 5.6ml / 100 page Yield
Color – CL-746s / 6.2ml / 100 page Yield

Standard Size
Black – PG-745 / 8ml / 180 page Yield
Color – CL-746 / 9ml / 180 page Yield

XL Size
Black – PG-745XL / 12ml / 300 page Yield
Color – CL-746XL / 13ml / 300 page Yield

if you not printing monthly, use the S size,
if you monthly print below 20 pages, look for Standard Size,
if your monthly printer more than 20 pages, you may look for XL Size

Page yield is the number of pages you can print with one cartridge. The page yield of a cartridge is based upon the ISO standard for measuring ink cartridge yields by printing out pages with 5% page coverage* until the cartridge runs empty. … It means only 5% of the page has ink or toner on it.