Its a mod done to the airbox. A 3-4" hole is cut in the airbox. A deckplate which has an outer ring with a removable center is glued where the hole is. When the center of the plate is removed it allows for more air flow into the airbox giving a small amount of horse power. If you are driving thru water or dusty conditions you put the center back into the deckplate to prevent water and dust from entering the airbox.
\/ Sold, BIG MISTAKE \/
'99 Tacoma, Black, 4wd, Ex-Cab, 4 banger, 2" RB,
3" CF,15x8 Eagle Alloys, 4.56 gears, CBI front tube bumper strewn with lights, 33" Firestone Destination MTs, Stubbs Rock Sliders, Multiple Decals for HP boost!