This lock is MADE OF SOFT PLASTIC. It looks the part but it is not robust at all, it may deter an opportunist thief from detaching your expensive Thule bike rack from your car but it's not going to stop a determined one. A small hammer and chisel could remove this lock in about 20 seconds (no joking here). The lock body should have been made from cast steel not injection moulded plastic (shame on you Thule). On the basis that something is better than nothing the this lock will do.
IF ANYONE KNOWS OF A BETTER WAY TO SECURE MY THULE BIKE RACK ONTO MY CAR PLEASE LET ME KNOW, I AM KEEN TO KEEP MY BIKE RACK SAFELY SECURED TO MY CAR!