I chose the LM555CN timer to sell because of its data sheet spec's. The regular 555 Timer Chips have a 750 or so Mw Rating the LM555CN has a 1180 Mw rating almost 50% more. This LM555CN timer also has a voltage rating from 4.5 to 16 volts. This is a great timer in the 555 series for the price. It is an 8 pin Dip package.