Tile, Modified 2 x 3 with 2 U Clips : Part 30350c | BrickLink
Amazon.com: Gobricks GDS-896 Tile, Modified 2 x 3 with 2 Clips - compatible with lego 30350 All Major Brick Brands Toys Building Blocks Technical Parts Assembles DIY (194 Light Bluish Gray(071),600 PCS) : Toys & Games