We installed the rear beeper/speaker just under the rear parcel shelf mount. This particular kit has a volume control to increase/decrease the beep volume. The tone of the beeper is also adjustable which is quite useful as we have found on occasion that older people sometimes struggle to hear the higher tone but the lower one is perfect.
Our customer had just purchased this 68 plate Nissan Micra and within a week had unfortunately damaged the bumper on a low wall he didn’t see!
Luckily the damage was minimal but it was enough to prompt him to decide to have rear parking sensors fitted, just in case!!