The  boots look rather ordinary. Tall, well worn, unadorned, and made of tanned brown leather . 

As a bonus action you click the heels together. The effects of the boots are active for the next 10 Minutes.

When you Activate these boots you roll a D20 and follow the following table

1-5
The boots become externally heavy and your movement is reduced by half.

6-10
The boots become lighter giving you an extra 5FT of movement.

11-15
The boots meld to your feet and almost becomes weightless  giving you an extra 10FT of movement.

16-20
The boots meld to your feet and becomes weightless doubling your movement.