This is one(1) pair of Grey rigid plastic armrests.
They fit most Invacare, Everest & Jennings, and most other wheelchairs with desk length arms.
Four (4) mounting screws are included.
There are 3 sets of mounting holes on the bottom, the spacing from center to center for each are:
3 5/16
5 1/2
6 13/16 inches.
***The overall length of the armrest is 10 1/2 inches.***