I had a problem with the system because of a power surge. I contacted customer service and they were great. They helped me get a replacement and helped me set it up.

This product is really awesome. It worth the price. Imagine you can get the dvr, 4 cameras with fine qualities and so on with only 100 dollars around. The quality of this camera video is totally fine. Night view is good too. The set up is easy. The after service is nice and patient.
Okay. With all the good aspects, there are some important tips for the new buyers. Just don't get the same lesson as mine.
1. This dvr only cooperate with monitor. Laptop is not included. If you get a TV , everything is just super easy. But if you try with a laptop, alright, it's a nightmare definitely.
2. The set doesn't come up with a Hard drive which is used for video storage. Usually one camera takes 20 G per day for recording, so you can count what's the memory GB you would like.
3. The set has many things, but not including the HDMI cable or Internet cables. Make sure you prepare that yourself.
4. For the cable included in this set, they are 60 feet/20m long. To be honest, it's just a medium length. I got extra 150 feet cables and cable connectors: male to female, power connecter.

I was going to leave a negative review but JAR from support really turned that around. Like other reviews, I had troubles connecting the NVR to the internet. Long story short, I had a bad NVR. Jar from support took care of me and sent out a new one and now I can connect to the internet. I also had another problem with one of my cameras. When I connected it, while watching my camera on live view, the bottom half of the picture was going from blurry to perfect back to blurry and was staying blurry at times. I contacted JAR again and he helped me out once again. I haven't tested out the other cameras yet do to the holidays but will after the holidays. But I know if I run into any other problems, JAR TO THE RESCUE.

Heres the deal. I installed these on a rental house where Im having tenant issues. For that purpose they work. They are inexpensive and I had access to my own hard disks.

The Good:
Camera quality is surprisingly good in both resolution and physical durability. They do not feel cheap and light. Hopefully time will tell how waterproof they are. The seller seems to have good reviews on backing up the warranty though so again we'll see how it all turns out. Its also nice the system can go up to 8 channels, so there is room to add more. The resolution is very good as well and it gives the choice of standard or high res when viewing the app depending on how fast you want the buffer to run depending on your connection. High res is extremely nice.

The Bad:
Software just sucks. Its a PITA to get working. Ive hooked up numerous systems, even my own SWANN system (which is very nice when you get it up and running) but this one just does NOT want to cooperate. First it makes you create a random account for password retrieval, which is odd because there is no reason to ever retrieve a password since logging on the system requires the "LOCAL" account password. For that you can simply reset the system. Being that this is a VERY foreign (Chinese) system, it sort of makes you wonder. Secondly getting the system just to start working with the app was insanely difficult and the instructions are HORRIBLE. I will explain below in my tips for setting up.
Also the android app (which I use) is pretty bad. It works on my phone (pixel 2), its works on my tenants phone (samsung) but is not compatible with my pixel C? Also it does require some odd permissions. Go in and turn off all the access in android that the app doesnt need like phone, microphone and any others. Im going to try one by one turning them all off until it just doesnt work. I dont like it wants local storage access (which might be for playback), location or camera either.
I would like to install this on my pixel c tablet but it is not compatible. Also On the samsung phone you can get a 4 window view but for some reason on my pixel 2 Im only able to view one camera at a time. Have NOT figured this out.

Now for some tips on setting up which I plan on possibly making a video for so others dont get frustrated:
No matter HOW MANY times I tried to set this up using the ip/domain settings it would not take. I personally prefer that method for trouble shooting and control. No matter what ports I forwarded in the router and brain unit it just WOULD NOT work. I decided to try the QR scan method. That got me no where for 2 different days at about an hour each. I FINALLY figured out when scanning the QR the app was placing about 20 random invisible digits after the QR serial. Once I noticed that I removed those and entered the LOCAL password and it finally connected. Again you set up a random account when you install the app but thats all its for, its very suspicious honestly.
Once the app was setup and connected though I got nothing but black screens on everything, all four cameras black. I then realized in the back I had connected the 4 cameras to slot 5-8 and not 1-4. Why this mattered to the unit is beyond me. Why the app just blacked out 5-8 even though it showed connected is strange. I placed the cameras on 1-4 and all of a sudden the app worked. On the actual unit all the cameras were viewing fine but the app is just really picky.
Tech support is ONLY in China apparently but when emailing through amazon I did get some form of support back from someone who emailed back some image requests. Be SURE to blot out any personal IP info if you do send this tech support images.
I next have to figure out how to utilize the record and playback plus setup an email account for image forwarding.

!!!!!!!!!!!!!!!! so the tips are !!!!!!!!!!!!!!!!!!!!!!
use LOCAL pass to login, NOT account pass!!!
Make SURE cameras are in the port in order or it will NOT work!!!
be SURE the app is not putting empty spaces after the QR serial when scanning!!!!!!!!!!!!!!!!!!

Fix the app and you have a VERY solid affordable camera system

Update - 5/31/19

I had to get a replacement system as the one I had continuously locked up and rebooted. It would also not keep the correct time, and this was an issue since installation but I figured it was a glitch and just memorized the difference. Also on every lock up it would reset the time if I changed it.

Anyway getting a replacement was easy but upon install I was again having trouble. I just couldnt get the thing to work with the app. Apparently theres a new app called ZosiSmart in the android store and though its the same DVR (I think anyway), I need to use the new app because the serials have changed. It gave me a little trouble and took a couple DVR reboots but it finally caught the signal and connected. Seems to work fine, thought the new app appears to catch and run a bit slower than the old. Either way, I have my camera system back up and running on my units and let me tell you, thank god I did this as it got me out of a couple jams in just the one year it was up. Im able to position the systems cameras to see all 3 houses and their parking, plus watch the street (which I already told the police in the area I have the system in case they ever need footage. I work very well with the department in my area and its very well reciprocated. If you own any rentals or a business its a really good idea to build a working relationship with whatever law enforcement covers your neighborhoods.

I want to especially thank Emma from ZOSI, who helped me through the process via email.

I bought this system almost a year ago to replace an old Q-See 1080P system I had that lasted almost 10 years. I was happy with that system, but after a car break-in at night where the video was grainy, even with floodlights on, I needed something with better picture quality. Two of the eight cameras died, but product was still under manufacturer warranty. I called support. After exchanging a couple emails with Slina & Ariana to prove that old cameras were broken, I was shipped replacements. They were white, and not black, like the original cameras that came with the system because they were out of black ones, but I have a full system that is operational now and you can't beat 4k video resolution.