After much research, I decided to buy the Atoto A6 PF 7inch Double-DIN Android Car StereoHD LRV, 2G+32G, A6G2A7PF. It appears to come with everything you might need, for installation, but I am writing this review to mention that you may need to know some information which took me a while to discover.Firstly, you may need to purchase separately, an additional wiring harness for CAN-Bus and steering control (steering wheel switches to operate volume, etc. when fitted to your vehicle). In some instances, the CAN-Bus unit is also needed to send the right signal to switch on a vehicle's factory installed audio system - otherwise you will install the Atoto and get no sound.Many modern vehicles use CAN-Bus (Controller Area Network) and you need the correct system for your vehicle. I'm not allowed to post links here, but there are some helpful videos online.Secondly, I am not an auto electrician, but I do have some basic electrical and electronic knowledge and have fitted regular radio/cd stereos to my cars, in the past. When installing the Atoto unit, even with all the adapter wiring harnesses, you are still likely to need to cut or join one or two wires to connect everything as you need it and achieve the required functionality.So, it took me a few hours across about 3 days, to get everything working as I wanted - mainly because I had to research help videos and harness supply companies, and order the correct parts, particular to my vehicle.In terms of use, the unit comes on pretty quickly after a few seconds, and if you turn it off during driving and then turn it on again, it has a stand-by memory which enables it to come on again instantly.The screen response is fast, like you'd find on a smart phone, although I have had to press quite firmly, at times, to get some menus. (Part of this may be because I am right-handed, driving a right-hand drive vehicle. This means I am mainly operating the Atoto with my left hand and at an angle to the screen).When using SatNav maps, some of the menu icons are quite close to the bottom of the screen and whilst I like the physical buttons on the unit, just below the screen, I managed to catch the off button when trying to press the tiny menu, bottom left of the screen for a SatNav menu. (This is more an issue of the App software, than it is the Atoto).Update August 2023:Having now used the Atoto A6 PF on a number of journeys, a few issues have arisen:Firstly, when using a SatNav app, it's only possible to have the radio on if you mute the audio announcements on the SatNav app. Otherwise, the SatNav audio will put the radio into 'pause', effectively switching it off and the only way to get the radio back on, is to navigate back to it and physically turn it on again. Contrary to the mentioned option of deciding the ratio of audio level, between SatNav and Media, this does not overlay sound from one to the other and back again. (On one journey, I had an opposite issue when the radio kept coming on and overriding the SatNav. The only thing that seemed to eventually stop this was to disable radio traffic announcements (TA).Secondly, using the feature of raising volume with road speed is not incrementally subtle - unless you are a person who likes to drown out all sound at very high volumes. It doesn't just increase volume by a little; it increases it be far too much. I now have this option switched off and simply adjust the sound from my steering wheel controls.Thirdly, Mobile phone data / Wi-Fi tethering seems a bit hit and miss. Sometimes the Atoto does not recognise my mobile (iPhone) hotspot and says 'out of range' - even with the phone an arm's length away. I even had the iPhone as one of my 'saved' connections - but it seems I sometimes have to manually connect, rather than it being automatic. And then it will recognise my passenger's iPhone hotspot and work fine; then, on another occasion it will recognise my phone again. All of this is further complicated by the number of options available to connect a phone with the Atoto: Direct USB cable from phone to Atoto; Wi-Fi signal from home Wi-Fi or mobile data with hot-spot tethering; Bluetooth and Bluetooth 2, where the second is supposed to transmit data, (which I thought might include the Wi-Fi from the mobile data). But with some 'link apps' you cannot use all of these options together and basically, have to pick one. (See more below).Fourthly, following on from the above, the uncertainty of whether a Wi-Fi tether, once connected, is staying connected, or not, can be an issue when using an App like TomTom SatNav with 'Live Traffic'. After a while driving, you may suddenly notice you haven't seen any traffic reports for some time and later discover the Wi-Fi link dropped out and did not automatically reconnect. It would be helpful to see a small icon on the display when a Wi-Fi signal is still active.Fifthly, I didn't have much success with 'Apple Car Play' and ended up downloading another link App. This works fine, but says...