This product from KEYSOURCE INT'L is a single keycap designed for blank keyboard applications, identified by the part number KBP-1391-1X1. It's a 'KEYBOARD BLANK' and 'KEY CAP COVER' from their KSI KEYBOARDS line. This individual keycap offers a clean, uniform look for custom keyboard builds or replacement needs.
KBP-1391-1X1 - Keysource Int'l KSI KEYBOARDS, KEYBOARD BLANK, KEY CAP COVERS