This is a flexible case, inspired by the Beats flex case. It fits BeatsX earbuds (As pictured) perfectly, and will also fit PowerBeats. I found that for standard wired earbuds, scaling the design to 70-75% is best. To use the case, simply pinch the sides of the case and the 'mouth' of the case will open so you can drop your earbuds inside. This is by far the easiest and sleekest to-use style of case for earbuds, wires, or anything else you can imagine. Rather than wasting time carefully wrapping wires around tedious parts like other designs, just bundle the earbuds up and drop them in; the case will keep them in place, and untangled. I printed the case pictured with cheap TPU filament I found on Amazon, however, all TPU's should work perfectly, and I imagine Ninjaflex would work best.