Greetings Jeff. Carl used a Perfectflite MT3G (miniTimer3) on his upscale Tres. <a href="https://www.rocketryforum.com/ctulanko/album/index.php?display=tres%2FTres%20440.jpg">Carl's Timer</a>. Based on his success using it I decided to place one on order for myself. My first test rocket will more than likely be a BT60 based 2 stage rocket.