The Rocket Beeper 1 (RB01) is an acoustic locator designed for use with model rockets. The RB01 has several advantages over other acoustic rocket finders. It has a DC-to-DC converter that boosts the 3.7 volts from a single cell lithium battery to 12 volts. This means that even if the battery voltage begins to fall, the beeper will still operate at its optimum voltage and produce a loud tone. To preserve battery capacity - and avoid annoying beeping on the launch pad - the RB01 uses a phototransistor to turn off the beeper when it is dark. This means that after you turn the RB01 on and put it inside your rocket - where it is dark - it will cease beeping until it sees daylight again after ejection. A battery is not included with the RB01; suggested lithium batteries are shown in the RB01 User's Manual. You can also use a 3 volt dry-cell source instead if you prefer. The RB01 User's Manual is available on the Data & Documentation page.