In general:

S is suitable for 1.0-1.6 Displacement

M size is suitable for 1.6-2.0 displacement

L size is suitable for 2.0-2.4 Displacement

XL is suitable for displacement over 2.4

specifications: Small size medium large size 4 models

? Product Packaging: ziplock bag packaging, can be customized blister packaging

the length of the product is only whistle, excluding the length of the holder.
About Size Selection:/Please first/Please measure the inner diameter of the tail pipe of your car,
compare with the size in the picture below to see which one is installed in your own car;
on the premise that the installation size is appropriate, try to choose a larger size.
Sound similarity: the sound made by turbo pressure relief valve of the sound is generally ". However, what this whistle sends out is "boo, boo", which is more inclined to the kind of mouth we play everyday Whistle whistle. After all, it is a few pieces of sound imitation device, which cannot be imitated to the same technically, only so

non-product quality problems do not accept returns