If this card is Normal or Special Summoned: You can add 1 "Assault Mode Activate", or 1 card that specifically lists "Assault Mode Activate" in its text, from your Deck to your hand, except "Psi-Reflector". You can reveal 1 "Assault Mode Activate" in your hand, then target 1 monster in your GY that specifically lists "Assault Mode Activate" in its text, except "Psi-Reflector"; Special Summon it, and if you do, increase its Level by 1 to 4. You can only use each effect of "Psi-Reflector" once per turn.
Psi Reflector, Assault Beast, and Assault Mode Activate actually make a good Synchro play enabler even outside of Assault Mode decks. Because of Psi Reflector’s level adjusting, you can use this combo to make any generic level-6 to 9 making it very versatile.
Discard Assault Beast to search Assault Mode Activate and setup your graveyard. Summon Psi Reflector then use his effect to revive Assault Beast.