An unbranded novelty clear mouse from China off eBay for four bucks including shipping illustrates just how simple optical mouse technology appears these days.
The label simply calls it Optical 3 D Mouse, Made in China
The little circuit board covers barely half of the floor of the heart shape with sparse components inside. The LED at the point end lights up and looks red through the red plastic case, despite the scanner's interpretation of the light as yellow.
The overall size is 3 1/4" x 3 3/4" x 1 1/8" tall—a bit wide for comfort but smooth to hold but very lightweight. The clear scroll wheel registers feedback notches. Two buttons cover the full cord end of the mouse and click nicely.
The specs seem respectable:
It is a cute novelty to keep around for a spare USB mouse, to contemplate mouse workings, or maybe to woo a valentine.