The number 8 is printed on part of it. It's 7/8s of an inch long. There's an open space where the metal part of the cabinet drawer goes into it.
A quick learner from Bentonville, AR says:
January 2, 2021
Clarification: The place where the metal bracket goes into measures 7/8 of an inch in height. That part is 2 and 1/4 inches long. The other side is 2 inches long.
Casey from SWISCO responded:
January 5, 2021
Hello, thank you for writing in. See our 32-018. Note that this screws in to the back of the cabinet wall as opposed to the plug-in type.