FAQ / comfort
Can I wear a running vest with a backpack?
It may be possible, but shoulder straps can overlap and rub. The Défi vest is not described as a backpack-compatible system.
Purchase, availability and delivery details are shown on Amazon UK.

Défi running vest · UK guide
can i wear a running vest with a backpack
Guide / 01
What the answer means for this product
The vest has shoulder pockets and straps, so another pack may block access or create pressure. No compatibility test or combined-load rating is published.
Guide / 02
A useful next check
Try both items together while stationary and check movement, pocket access and strap contact. Use a different carry arrangement if they interfere.
Good to know
Questions, answered.
Can I wear a running vest with a backpack?
It may be possible, but shoulder straps can overlap and rub. The Défi vest is not described as a backpack-compatible system.
Défi The Elements