This leds are the perfect mate for handheldlegend two part buttons, easy to install and very tiny, ideal for modding. I'm in love with these.
These little LED's put out just the right amount of light in a small package that can mount in a bunch of places within the tight confines of the various Gameboy platforms. The fact that the LED is at a right angle is also genius. You can mount the LED flat on the surface and just angle the LED towards whatever you want lit. The solder pads are tiny, so make sure you have a magnifying glass handy. I also recommend tinning the tips of your small gauge wire before you solder to get better connections.
Also, since it's not listed in the product description, I'll save you some time figuring out polarity. With the LED facing away from you and the 2 solder pads facing towards you the negative pad is on the right and the positive is on the left. For those of you that color match your wires, this will be a time saver.