This product can be severed as main switch, automotive start relay and battery isolator. Put this relay between batteries as an isolator or in the main power. 

Features:
Red copper binding post: ensuring heavy current can be transited safely. 
High current automotive relay and battery isolator.
12V 500A heavy current relay: great for construction and machinery system.
High quality: ensuring the maximum electric current can be transferred.
Easy and effortless to use: simple installation.

Practical replacement battery pack for your choice, it can work with many power tools. With large capacity, it can work for a long time.

Features:
Great replacement battery, it can work with many power tools.
Large capacity battery allows long time working which lasts much longer than usual battery.
High quality material, high product standards, protection from short circuit, internal overheating, overloading and overcharging, long service life and safe to use.
Impact-resistant outer case and shock-absorbing inner-liner are engineered to protect the battery.
No memory effect allows to charge at anytime and virtually no self-discharge is for maximum working efficiency.
Suitable for working with power tools, electric drills, gardening tools, etc.

This battery USB charger can charge six batteries at the same time, light and portable. It can be connected to mobile phone charger, charging treasure, computer USB socket. Very convenient!

Features:
USB standard power supply interface, easy to operate, plug and play, can be connected to mobile phone charger, charging treasure, computer USB socket.
Six channels of independent charging output, can charge six batteries at the same time, smart charging, full charging will automatic stop!
It supports LiPo RC battery, and support 0.2A/0.6A charge current by switch button.
6 LED indicators independently indicate the charging status of the six channels, the charging process flashes, and the charging completed bright constantly.
If you have any problem, please feel free to contact with us without hesitation.