This is the intention behind the different bag sizes:
wristlet -- for minimal carry, a phone plus a few cards, maybe a slim minimalist wallet
maya -- small purse for personal carries like phone, wallet, keys, a chapstick...
mini-reve -- like a small purse, but just a little bigger so it fits an ipad (not ipad pro)
s/m-reve -- fits a small laptop with protective sleeve (like a 13" laptop) plus personal items
large-reve -- fits a large laptop with protective sleeve (like a 15" laptop) plus more...
yume -- size is ideally* just a little bigger than the mini-reve (*ideally not stuffed up).
To compare the reve's, this photo might help: https://www.instagram.com/p/BD8v17NCEU0/?taken-by=byasum
Please see dimensions above for more.