Do these bolt directly to my roof rails or do I need extra hardware?

These mount at factory attachment points on your existing roof rails. Confirm your vehicle has factory rails installed before ordering — the mounting method is designed around OEM rail geometry.

Will aluminum crossbars hold roof box weight?

Aluminum is strong enough for typical roof cargo like boxes and carriers. Check your vehicle's roof load limit in the owner's manual and factor in the crossbars' own weight before loading.

Can I return these if they don't fit after I open the box?

Test-fit these against your roof rails before removing any packaging. Contact ModSupply support with photos if fitment issues come up — they'll work with you on next steps.