Protection circuit built in so you can't drain the batteries too low or overcharge them. 5000ma for long run times. There are no other 21700 batteries on the market that will give you longer run time in our lights then these.
We are a Texan owned and operated company. We are based in the oldest town in Texas and we pride ourselves on our Southern hospitality and customer service. We look forward to helping you with all of your night vision purchases and answering your questions before and after the sale.