This is the one-key system that locks the Mach2 into the hitch and the Add-ons together.
You can see the red safety latch that connects the Add-ons together and the blue push-button barrel lock that protects it from being removed.
The same lock and key are used to lock the rack into the hitch.
You will receive 2 keys with the Mach2 hitch rack. If you purchase more Add-ons later down the road, we can look up what variation of lock you already have and match it to your existing keys. Additional keys can also be purchased.