The Cover, Key and Lock Barrel kit comes with 2 keys, 4 metal lock cores and 4 plastic covers, so you can lock up all 4 corners of your roof rack.
Installation is easy. Simply insert a metal lock core into one of the plastic covers. Once this is done place the key in the barrel and try it out to see if it turns. If it doesn’t turn keep the key in the barrel and gently push the barrel out of the hole from the backside. Rotate it 90 degrees and try again until it turns without any issues. Finally slide the plastic cover over one of the feet of your Modula Roof Rack and turn the lock to secure it.