As it says on the web page,"Adjustable Via the Eccentric Crush Tube".
That's the bolt that holds the 2 pieces together. Looks like you can turn the bolt side for adjustment then use the double nut side to lock it.
I'm surprised the directions wouldn't mention that.
(At least that's my take on it.)
14 V6 auto, MCA, PP, BBK Shorties, MMD Hood Struts, Borla Touring A/B's, MAC ProChamber, aFe drop-in Filter
Lets not forget, an opinion is a judgment, viewpoint, or statement about matters commonly considered to be subjective.