Originally Posted by
jrzyshawn
45 linear in or 115 cm (L+W+H), 40 lbs or 18 kg.
Rarely enforceed though.

I'll agree on the

for size (and quantity), but not on weight. At least CO allows 40lbs, which allows you to carry actual things. The 7kg limit on many European and Asian carriers is perhaps enough to put some air into your bags (most rollaboards are ~3-5kg).