What is the difference between the max power .12 exhaust kit 2670 and the 2694?

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I am looking for the same and can't find it

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They are made by Hipex. They look like Hipex 2669 and 2688.

Looking at pictures on the Max Power website, it looks like 2694 has the pulse reflector further back in the resonator, producing a shorter return path and optimizing the exhaust for operation at higher RPMs.

https://rcmaxpower.com/en/16-mufflers