These are wall brackets for the sheet music holder of my Yamaha P-45 digital piano. My problem was that the piano has to sit flush to the wall and the sheet music holder therefore interefered with the wall. So I designed a holder which both enabled me to attach the holder to my wall and to place it higher up. Probably the brackets do also fit other piano brands.

You need to print two of the holders and you need 4 M4 flathead screws.