This is the Traxxas Super-Duty Long Glow Plug.  This works very well in all Traxxas engines, including the Pro .15, TRX 2.5, 2.5R, and 3.3 engines.  This works in the Revo, Jato, T-Maxx, Nitro 4-Tec, and other nitro vehicles.  These plugs work with the EZ-Start system glow plug wire.