Detachable Backpack Backpack With Detachable Daypack?

Backpack with detachable daypack? - detachable backpack

Hello does anybody know where I can find a backpack with a removable backpack, but it is only normal pocket size of 47 cm in height. He used to be a limit on the local market, but we do not sell ... I find a site boundary. You want to pay no more than 30 pounds and do not care about brands.

Thanks