Levitation boots

From Memory Alpha, the free Star Trek reference

Levitation boots were used to propel an individual to heights that the user would normally have to reach by climbing or using bulky equipment. The boots were of a fairly standard size, with the booster (or perhaps thruster) in the heel of the boot. Levitation boots were designed to propel only a certain weight (presumably around 600 pounds, or three Human men) but may have been designed for use by heavier officers and species. Furthermore, levitation boots were capable of firing the booster rockets which resulted in a very accelerated speed. Also, the boots seem to have the capability of allowing the user to hover in the air while the boots were inverted.

In 2287, Spock used the levitation boots to observe Captain James T. Kirk while making his ascent on El Capitan.

Kirk, Leonard McCoy and Spock also used the boots in an attempt to climb a turboshaft while being pursued by Sybok and his followers on the USS Enterprise-A. (Star Trek V: The Final Frontier)