|Allows you to convert your REX R1 into a full function R2! Installs onto your existing board in minutes with no modifications required! (Plugs in at the bottom of the electronic board). Provides Full-Auto, Semi-Auto, Burst and more! Also works on many older Odyssey Black Dragun markers. Fits onto the existing board. Full Function! DOES NOT INCLUDE BOARD! ONLY THE UPGRADE JUMPER CHIP.