... button type: A:on the bottom of the front cover;B:on the right side of the front cover7.Built-in ... camera optional8.17.3",18.5",20",21.5",23",24"skd has the same appearance. ROWA Digital (SHENZHEN) CO.LTD ... ,Drive board... Full set of products and accessories ,services supply 24" (16:9) Wide-Screen led display