Securely mount your MAXTRAX Xtremes on your roof rack bars! The set includes 4 pins that can securely hold 2 or 4 MAXTRAX Xtreme (1 or 2 pairs) 4WD Recovery Tracks, 4 stainless steel Nyloc nuts, and 4 flat stainless steel washers. There's a hole in the top of each mounting pin to fit a small padlock.