600P/R Incremental Rotary Encoder,2-Phases Photoelectric Encoder 5V-24V,Shaft 6mm Encoder Wide Voltage Power Supplies

Good build quality, operates well at 5v and is simple to hook up to Arduino board to read the value.

if you look around for an optical encoder you see this model (even with the same stickers) everywhere! You may think that this is due to being cheap off-spec, low quality parts. Actually, it is exactly the opposite. They are quite heavy and very accurate. the shaft rotates without resistance and stays in place without dragging back. moving it or shaking or around does not move the shaft. The output is stale without jitter or noise.Search for the first random tutorial on how to use this with Arduino and you will find tons of wiring diagrams and code to test it. it works right out of the box.Great value for projects.