The SparkFun COM-11992 is your basic red action button!
This is a very useful, small, panel-mount momentary switch. It is a SPST N.O. with 1/4" threading. This button is perfect for basic On/Off functions. Overall length (including leads) is 1.06" and has small solder lugs for connection. These momentary buttons are rated up to 0.5A and 250VAC.