We call this catch the Seitz Ledge. As you can see it has aledge running along the bottom edge of the handle. They come in right and left handed versions. We recommend that you fit our devices to the bottom (horizontal) catches of your windows.
You can add/remove required quantities at checkout.
We cannot accept payments at checkout from overseas. Please contact us on +44 7446 911 511 if you are ordering from abroad.