Here are some pictures of the Crossbow Powerlock. The entire (black) centre line is replaced as it is fixed securely to the reinforced end near the QR. In addition, I am using a smaller chicken loop so I still employ the same arm stance.
Engagement is similiar to the Recon powerlock: pull the bar down to engage. To disengage, just twist your wrists with downward pressure. So really it is no different to earlier Cabrinha powerlocks.
Handy also, by flipping your centre line/chicken loop over 180deg, their is no accidental engagement. Cost for me was ca. 50AUD.
Edit: updated links as host server moved photos