I made these to do a ridiculously high dunk

Summary by Krater

The creator builds extendable pneumatic stilts—dubbed dunk boots—designed to let him dunk a basketball from 16 feet high, and successfully tests them after overcoming several mechanical challenges.

From the video

Answers: How can you build pneumatic stilts to dunk a basketball from 16 feet?

• pneumatic stilts
• dunk boots engineering
• telescoping tubes
• air cylinders
• basketball dunking mechanism

What it concludes

• Connecting the stilts to the pneumatic legs with custom 3D printed O-ring seals successfully prevents air leaks.
• Using an automatic belay system is necessary for safety when testing high pneumatic stilts.
• A roller coaster track guide prevents the stilt legs from jamming and shooting up uncontrollably.
• Switching from a cable system to a metal link chain solves the problem of cables getting tangled and kinked during stilt retraction.
• Adding foot rests and balancing the stilts allows the creator to successfully dunk a basketball from 16 feet high.