'In-mirror-monitors' are the most popular type as they are so discreet.
They are also in the natural line of sight between the door mirrors and the the interior mirror which you scan whilst reversing.
Glancing at the monitor is therefore 2nd nature.
When you select reverse gear, part of the screen switches on to show what the reversing camera can see.
See instantly that big blind spot behind you.
When not in reverse, it looks like a normal tinted mirror, so your vehicle looks factory standard.
Choose either the 'replacement' type if your vehicle has a compatible wndscreen mounting as shown, or choose the 'clip-on'.