Small/applicable displacement: 1.1-1.6 Applicable exhaust pipe caliber: 32-43 mm Medium/applicable displacement: 1.6-2.0 Applicable exhaust pipe caliber: 37-48 mm Large/applicable displacement: 2.0-2.4 Applicable exhaust pipe caliber: 44-55 mm Plus/applicable displacement: 2.4 and above Applicable exhaust pipe caliber: 56-85 About size selection: Please measure the inner diameter of the exhaust pipe of your beloved car first. Compare the size in the figure below and choose the right one. The size of. Under the premise that the core is suitable, try to choose a large one. Sound similarity: The sound of the real turbo pressure relief valve is generally "h, bare", and this whistle is "boo, boo" Prefer to whistles in favor of our daily play. After all, it's just a few-piece sound imitators. Technically, it can't be imitated as the real one. That's all. 100% brand new and high quality Make your car sound like furious, turn your car into king of the road, fashionable and unique, improving your driving interest. After installing this product, the pressure blowing out of your car's exhaust sounds like a turbo vehicle. Made of high-quality aluminum, lightweight and durable, easy to install on the car's tailpipe, universal fit. Place the turbo sound whistle body inside the exhaust muffler with the larger opening facing the inside of the muffler. Made of premium quality aluminum, light weight and durable. Easy to install on the car's tailpipe. This whistle can be installed under short minutes. Package Includes: 1x Turbo Sound Whistle Specifications: Material:Aluminum Color:Black/Blue/Gold/Red/Silver note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3.Confirm the size of the exhaust pipe before purchasing. The size of the exhaust pipe must be larger than the product size before it can be used.