Onyx it. The Onyx mesh marker tray organizes your whiteboard dry erase markers and eraser within reach. Up to four markers stand up vertically for quick use. Five inch wide shelf holds your eraser conveniently underneath your markers. This smart marker tray has a magnetic back that allows for use on magnetic marker boards rumba models 2014Wbs, 2015Wbs, 2016Wbs and 2017Wbs or impromptu models 8511BL and 8511Gr (sold separately). mounting hardware is also included for wall mount. Steel mesh construction with durable powder coat finish.