The XLAB Sonic Wing Rear Hydration System has been specially designed to fit Cervélo P2, P3, and P4 bicycles. It is also compatible with the Quintana Roo PRsix. If you look closely at the seat post, you’ll notice two holes into which the Sonic Wing securely fits. In fact, if you see “Sonic” in any XLAB product name, that is an indicator that it has been designed with Cervélo in mind. In this case, the Sonic Wing has been developed to give you a method to carry your hydration and repair kit needs with no aero handicap or excess weight. It is an all-in-one platform to attach your XLAB Gorilla bottle cage and XLAB Mezzo bag, for instance, to carry all your water and repair essentials. Since it is position at the rear of the saddle, it provides the added benefit of filling in the turbulence hole behind your backside, thereby reducing drag. It might be hard to imagine, but there are 30 different positions available, so that you can have a custom fit position that is both comfortable and aerodynamic. There are also three different carrier angles and five different bottle angles for each position. And if you have been resisting investing in a setup of this sort because you dread the accompanying rattle that often results with these sorts of devices, you won’t have to worry about anything like that with the XLAB. That’s because XLAB designers have taken the precaution of using anti-vibration hardware including Loctite screws. The Sonic Wing will be extremely durable as well since it has been constructed out of high-quality aluminum. It remains a light affair without stepping into expensive carbon material territory. Since the Sonic Wing attaches to your seatpost and not your saddle, you should not have any compatibility difficulties no matter what saddle you sit. The XLAB Sonic Wing Rear Hydration System comes with one X-Strap to facilitate attaching your XLAB Mezzo bag. You can also make use of the Sonic Nut if you are concerned about having your inflation equipment super handy. With included hardware, the Sonic Wing weighs just 95 grams. Lightweight and aero, you’ll always be well equipped when you use the XLAB Sonic Wing Rear Hydration System.