This is a very very bright blue SMD LED. Voltage drop is 3.8 Volt at 20 mA, use an 68 Ohm series resistor for use with a 5 Volt supply. Do not look directly into the beam. The missing edge is the negative side. Also available in white.
This is a surplus product. It was obtained from a surplus store, from an inventory or from any other secondary source. You can expect this product to be in good working condition, but it can show signs of being handled, shipped, repackaged etc. The supply of a surplus article can suddenly run out, or the price can change. Get it while it is available.