Backpack of Walking/Climbing

This is a thin backpack that can be worn under an adventurer's pack or other bags. This bag has 6 small feet that hang off the back. When activated, the legs extend and loft any creature (small, medium, or large) into the air not far off the ground. On your turn, you can use a bonus action to activate the backpack. Once activated, your walking speed is increased to 50ft. and you have a climbing speed of 50ft. 

Once Attuned to this wonderous item, you can activate the backpack as a bonus action. 

Notes: Set: Innate Speed (Climbing), Set: Speed (Walking), Once Attuned, the backpack can be activated with a bonus action.