TOOGOO(R) Two Way Mount Universal Muffler Fake Turbo Sound Simulator BOV 30mm Product Name : Turbo Sound Whistler Fit for Tube Inner Dia. : 30mm/ 1.2" Fit for Exhaust Pipe Thickness : 12.7mm/ 1/2" Screw Diameter : 6mm/ 0.24" Whistler Size : 63 x 30mm/ 2.5" x 1.2" (L*W),Total Length : 106mm/ 4.2"