These are Black boots with Red stitching with a aggressive sole that looks like it would provide very good traction. The top of the boots extend 9" high up on the calf with boot laces. 

once fully laced up and attuned the attributes becomes apparent.

1: they act the same as a freedom of moment spell (movement is unaffected by difficult terrain, and spells and other magical effects can neither reduce the target's speed nor cause the target to be paralyzed or restrained. The target can also spend 5 feet of movement to automatically escape from non-magical restraints, such as manacles or a creature that has it grappled. Finally, being underwater imposes no penalties on the target's movement or attacks.) with the addition of air.

2:  yes the wearer of these boots can step on air.  basically each boots acts like a immovable rod. in fact they have been infused with the same enchantment. each time the wearer picks there foot up is the same as pushing the button on a immovable rod. allowing the boot to move. each time the wearer puts there foot down is like pushing the button again and the boot can not be moved if the wearer dose not want them to be moved. the wearer has complete control over this and can turn this feature off by will. to turn this feature on or off you have to be awake. if you are knocked unconscious while in the air you will remain stuck in that space.  

the wearer of these boots never sets off any floor traps that require pressure, nor dose the floor ever squeak. you get advantage on stealth checks in regards to sound produced while walking. but only if you have that feature activated. 

The boots can hold up to 8,000 pounds of weight. More weight then that will cause the Boots to deactivate and fall. A creature can use an action to make a DC 30 Strength check, moving the fixed Boots up to 10 feet on a success.

movement over air is the same as moving over land. to move up or down is the same as climbing steps. 

Notes: Bonus:  Stealth, Movement, Utility, Footwear, ultimate freedom

Notes: Bonus: Stealth, Movement, Utility, Footwear, ultimate freedom, requires attunement by a creature that has feet. must be worn on feet. , Utility, Exploration, Footwear