Upgrade your reclaimed boxes and bags with sturdy 2-3 mm galvanized wire...

https://packagingrevolution.net/add-wire-handles-to-boxes-and-bags/

Upgrade your reclaimed boxes and bags with sturdy 2-3 mm galvanized wire handles for a reliable grip that lasts. Drill 3-3.5 mm holes to thread the wire through easily without tearing the material