Originally Posted by Ingleside

those are 25.4

7/8th is typically the clamp diameter on BMX bars. mountain bike stems and bars are typically 25.4 or 31.8 so you are going to have a hell of a time trying to find a riser bar in 7/8.
you may have some luck looking for a micro or mini bar designed for younger bmx riders, although they are meant for really light weight riders.