You love NeoPixels, and you love silicone diffusion? Peep this Flexible Silicone Neon-like Skinny NeoPixel LED Strip! OK it's a bit of a mouthful, but check out the beautiful footage! It looks a lot like a slim strip of neon, but without the need for expensive transformers, glass tubing, inert gasses, or a Las Vegas casino license. They look incredible, are super easy to use, and are a great way to make your projects light up!
It's flexible, skinny, and bendy - basically its one of our side-light NeoPixel strips, with a solid casing of translucent silicone rubber as a diffuser.
The silicone makes for a strong, durable weather-proof casing. While not guaranteed for dunking underwater or long-term outdoor exposure, they're durable enough for projects that have to survive the outdoors, like cosplay, bike lighting or festival decorations. You can cut this stuff with wire cutters.
You'll get 1 meter long tube that is sealed at one end, and has a JST SM 3 pin connector in the input. Provide 5V on the power pins, and provide your standard issue NeoPixel (WS281x) data on the third pin - don't forget to share the ground pin between the 5V power supply and your microcontroller. Boom - you're glowin' in style.
Adafruit's detailed NeoPixel Uberguide has everything you need to use NeoPixels in any shape and size. Including ready-to-go library & example code for the Arduino UNO/Duemilanove/Diecimila, Flora/Micro/Leonardo, Trinket/Gemma, Arduino Due & Arduino Mega/ADK (all versions)