[power switch ] the advantage of this battery is there is an additional switch within the battery that enables the user to control the power supply by turning the key after putting the battery in the bike. note: open the lock firstly . [after-sale service policy]our 48v moutain bike lithium-ion battery is supported with one month return(except you order wrong battery, please double confirm which you need before booking), 12-month quality assurance [ fast divery]the electric bike battery is shipped from ca, us eu warehouse, normally it takes 2-7 business days to delivery to you. if, you need to return or exchange battery, it is very convinent to the us warehouse. [shock & water resistance]the 48v ebike battery is made of strong abs pc shell, and meet with water-resistant ip65 level, means you can ride in a small raining for a moments, but not too long, to make sure the battery life. [bms strong protections]the electric bicycle battery is built-in a 30a bms to protect the e-bike battery from overcharge, over discharge, overcurrent, overvoltage and short circuit, etc, extend the electric battery pack life, it is up to 800-1000 times( 5 years)..syi