Help spec me a suitable rucksack

[RoboCod]

Hi, the other half's dad wants a rucksack for on the bike. The thing is, he doesn't want a bag specifically designed for riding on a bike (like I would suggest). He is hooked on a military style bugout bag since he caught glimpse of mine. I think he likes the molle systems and straps etc.

I don't ride so was hoping anyone had any pointers. I was looking at this one but I think it might be too deep/big?

https://www.amazon.co.uk/gp/aw/d/B01KX29BXQ#Ask

 

[RoboCod]

See that's what I thought, but he has specifically said he doesn't want a bike bag but something like what I've linked. Like you say though, I also thought a big bag would be a pain.

I don't want him to be disappointed with something he didn't want, but I also don't want him later down the line to be fed up with an inappropriate bag.

Silly bugger ought to know better, he's been a Biker for years!