Rear Hub spacing on Cervelo P3C for PT SL

Looking at getting a PT SL, but it comes in 2 sizes (I think) either a 130mm or a 135mm…Who knows the right size and/or better yet where the heck do you find that type of info???

Slow Engine on a Rocket

135 is for mountain bikes and some cyclocross frames. All modern road bikes need 130.

Thanks!