From our 11 years' experences in parking locks and some agents need,2011~2013 we designed, after many quality tests, 2014 we assured that  are the below : 
 Battery is 3kg, 1 year only charge 1 times 
Don't need recharge the battery every 3 months
Real 5  Tons overloading ability
Don't worry it will be broken when it is driven over,   such as some  luxury/heavy car :Audi A8 series&BMW 7 Series&Benz S600/Porsche and most Jaguar Land Rover, it is no any question.
Waterproof Protection Grade is IP68, can be kept in water about 24 hours 
Don't doubt that if it can work at the always rain  weather,  no question.

 It is called as AS-BW-15, it is produced by ANSAI,  It is the best in the world now.