Being on an island with much free time on my hands at times, I spend some of the time designing a freediving noseclip that is fairly easy to make using readily available materials! The latest version, while not the sleekiest, turned out to be quite comfortable. Zero carbon footprint. 100% leftover bamboo! With a little strip of used rubber to prevent slippage from the nose, it works great for static. Waterproofed, it could perhaps be tested for depth training.
Disclaimer: This design is not a substitute for a proper commercial freediving noseclip. This may not be suitable for depth training. Do not attempt freediving without attending a formal freediving course.