A general assortment of transistors and diodes. A great introductory kit which includes paper booklets which gives and overview overview of the basics of how the components work as well as some example circuits.
Includes a wide variety of LEDs, current limiting resistors for using those LEDs with a wide range of voltages, and advanced driver circuits. The kit it great for anyone trying to learn more about LEDs and how to use them. It's also great for keeping parts on hand.