Carabiner Oval Keylock. Black Diamond OVAL CARABINER KEYLOCK is the iconic, symmetrical OVAL.. It has stood the test of time, and will now remain essential to your rack due to the new Keylock snag-free design. With its large rope-bearing surface, improved ease of use, and smooth uniform shape that reduces carabiner shift, the OVAL will continue to get the job done on the world’s hardest big walls.