4 wheels for an office chair (crouch end, N8)

These have been taken off our 5 wheeled office chair as one was broken. These four are fine and can be used for an office chair with 4 legs. Standard size 11mm wide at top 22mm length. I believe this is a standard size EXCEPT FOR IKEA chairs. So, not suitable for IKEA chairs.
There's a limited amount of wear on the wheels but otherwise in good condition. See photos.