What is a VESA mount and how to know what type your TV has
Those 200 × 200 and 400 × 400 numbers tell you where the mounting holes line up, but you still need to check the mount's weight limit and hardware.
Those 200 × 200 and 400 × 400 numbers tell you where the mounting holes line up, but you still need to check the mount's weight limit and hardware. Source
