I ordered this from China based ebay seller for £13.29 on 09/03/16 it was posted on 12/03/16 and arrived 24/03/16 so thought id do a quick review.

Blurb
Working based on existing GSM/GPRS network and GPS satellites, this product can locate and monitor any remote targets by SMS or internet. The most advanced technology of GPS and AGPS dual positioning. The waterproof level achieve IPX-6. It can be used for electric vehicle, motor bike, truck, car, etc.

Features:
Mobile phone monitors your vehicle anywhere anytime simultaneously.
Waterproof, shock-resistant, dust-proof.
Shake and location moving alarm.
GSM four frequency(GSM850/900/1800/1900MHZ) system global general.
Built-in switching power supply, exceed wide voltage input range: 10-75VDC.
GPS continuous GPS positioning, GPRS report regularly.
Surpport SMS message to check the location info.
Built-in vibratin sensor, realization vehicle anti-theft intelligently.
ACC the ignition signal detection, vehicle status prompted.
Built-in backup battery, realize the illegal cut the line alarm.

Specifications:
Alert Type: SMS, Phone Call
Network: GSM/GPRS/GPS
GSM Network: 850/900/1800/1900Mhz
Voltage Input Range: 10-75VDC
Package Size: 14.5 * 9.5 * 3cm / 5.7 * 3.7 * 1.2in
Package Weight: 134g / 4.7oz

Package List: K2129
1 * Host with Power Cable
1 * User Manul

Testing

The manual was written in plain Engrish which is unsurprising considering they spelt ‘Manual’ wrong in the description.

I put a known working sim card in and waited for the flashing green and blue lights then I sent the SMS message

G123456#

123456 is the default password for the unit. Within I minute I received a reply on my android phone containing a google maps link and some other info

http://maps.google.com/maps?"Coordinates" V: A,2016-03-25 02:28:46 S:009km/h,Bat:6ACC:off,4210103769,S19G06;p:23410, l:21571, c:12434

Clicking the link opens google maps and shows current location, I must say I was very impressed as it was absolutely bang on where I was, this is the advantage of having GPS GPRS functionality over just GRPS which the other unit I tested had.

Breaking down the message.

http://maps.google.com/maps?"Coordinates" where I have written “Coordinates” is obviously where the longitude and latitude numbers were i.e 00.00000%2c000.00000

V: A,2016-03-25 02:28:46 This is obviously the date and time of the last position but for some reason it’s 8 hours ahead i.e China time, not sure if this can be changed but will look into it.

S:009km/h Current speed at time of query in km/h which equates to be about 5 mph, curious thing is that the unit was stationary in a building

Bat:6 Battery level indicator? TBC

ACC:off Accessory switch position

Changing the unit password

The default password for the unit is 123456 to change it to something more secure send the following message to it
pwd123456 654321 Where 123456 is your current password and 654321 is your new password

Shortly after you should get a reply saying
OK! New password: 654321.
Safe keeping!

I then did a test message using the old password of 123456 and I did not get a reply, I did the same again using the new password 654321 and I got the location message as expected.

Anomalies
The included instructions refer to the fact that the device has a backup battery installed but no further information. It’s also shows a picture of the device highlighting the usb port but makes no reference to it. The usb port is a standard micro usb as used for a lot of mobile devices. There is no charging plug or lead included so my next job is to confirm that this port is indeed for charging the device and also on how the ‘battery backup’ feature works as there is no physical on/off switch to use it adhoc for example.