Gravity boot

Magnetic gravity boots were footwear worn by Starfleet officers, and presumably other spacefaring civilizations.

These boots provided stability by adhering to a compatible surface, useful when sufficient gravity (or artificial gravity) was not available, including extra-vehicular environments ("space walk" situations).

In 2063, Captain Jean-Luc Picard, Lieutenant Commander Worf and Lieutenant Hawk all wore gravity boots while on the hull of the USS Enterprise (NCC-1701-E), so they could destroy a Borg interplexing beacon located at the ship's navigational deflector. 

In 2152, Lieutenant Malcolm Reed wore gravity boots attached to his environmental suit in order to disarm a Romulan mine lodged on Enterprise's hull. 

In 2154, Commander Charles Tucker III, Malcolm Reed and two MACOs activated their gravity boots after boarding the Romulan drone-ship. 

In 2293, Yeomans Burke and Samno wore magnetic gravity boots to assassinate Chancellor Gorkon, while artificial gravity was knocked out on Kronos One. Lieutenant Valeris later stowed one boot in Crewman Dax's locker to implicate him in the assassination.