Needed a backup so we will always have one chargedHave not used it yet but it will be used for a leaf blower and a grass cutter.Angela at BP Solutions went over and above to satisfy this customer! A valuable employee, a job well done and a satisfied customer.The battery package is a nice design. I particular I like the following;1. you can check the status of the battery by pressing a button on the battery, at any time2. it has a handle for carrying it, which is REALLY handy in the field when you want to carry it with the one available finger. Yeah, you know what I am talking about.3. It runs and charges cool. I just used it through 2 charges on a weekend running full bore and it just got warm in use and during the charge.4. It really delivers performance and duration.I am a professional: both in electronics and battery power but I also own a timber farm. I could feel the saw talking to the battery and changing the torque to match the current availability. Furthermore I felt that it was making really pragmatic judgement. I am impressed.I may have small issues with the saw design, but these folks nailed the battery management part. They also nailed the battery package design. Congratulations!== just a user/customer. Not paid or reciprocated in any formRevised, after 2 yrsWell one of my 2 batteries failed. On board indicator showed full charge but as soon as I tried to use it, it went to zero and would no longer charge.I tried the hold for 5 seconds reset, nopeA web search indicates that these batteries have serious reliability issues.I submitted a support ticket to Echo and will update this laterJunk. Second time with a new 4amp hr battery. Dead right out of the package. So disappointed. I have to pay to return it to seller ,even though its was defective. What a scam. Echo makes good tools,gas and battery,but the 4hr batteries are junk. Dont waste your money. I will be changing over to e go. It's a shame,I have 4 of the echo 58v tools,but can't get a good battery for them. Yard sale time I guess. After several emails to ECHO, and running around to ECHO dealers,i wasted several hrs,my gas,and then was charged$30.00 by the authorized echo dealer for him to tell me that the warranty doesnt cover my battery issues! 30.00 freaking dollars for wasting my time??? NEVER AGAIN! DO NOT BELIEVE REVIEWS!! ECHO TOOLS ARE NICE,BUT BATTERIES AND WARRANTIES ARE BOGUS!! IVE HAVE WRITTEN THE BBB ABOUT THIS ISSUE ALSO. JUNK...IF YOU'RE SMART,AVOID ECHO!Update.... After contacting the seller, theydid an awesome job with helping me out ! Outstanding service,thank you very much!Still very disappointed with echo batteries. I can't understand it,the 2amp hr batteries work great,just dont last long,especially in the lawn mower. Everybody else seems to have a grasp on the battery concept,except echo. They claim a 5 yr consumer warranty, but good luck with that.Update 2: Every battery that came with my echo tools is now dead. Warranty will not replace them unless they were purchased at an authorized echo dealer. Doesn't matter if it's an echo product,with their name and logo,THEY WILL NOT WARRANTY OR REPLACE IT. After some shopping and research, I found it's cheaper to buy an entirely new tool and battery than to replace just one battery.I CANT EMPHASIZE IT ENOUGH! I WILL NEVER BUY ECHO JUNK AGAIN. PRODUCTS STINK,AND CUSTOMER SERVICE IS NON EXISTENT.I used this battery for my leaf blower and was surprised at the power it had for blowing wet leaves and small branches.I've only used it to full discharge twice and it's longevity is about 50 minutes at medium power. However, it charges fully in only thirty minutes . My original battery for the blower is good for thirty minutes so I have continuous use of my blower if needed with both batteries. I hope the battery life is as good as its performance.The only issues preventing full five stars is the battery weight but it's lighter than most others of same or similar size. It is a bit pricey also but if it lasts for a couple of years it will be well worth its price.This replaced a 2.0 amp which quit charging. As the original quit working after a year, I kept all the paperwork in order to take advantage of the 3 year warranty. I also read the instructions this time and plan to take new battery off charger after an hour of charging. So far i have done so. This 4.0 amp new battery truly powers the blower twice as long as the 2.0 amp. I hope with proper care it actually has longevity (something i cannot rate at this time). I do not believe anyone is pleased with lithium ion battery life or cost. This source was cheaper than Home Depot.Do not buy this battery. It worked maybe twice, then lost all its charge. It will indicate full, and when inserted into the mower it stays on for a second, then the mowe dies. I have another battery and the mower works fine with it, so I know that the problem lies with the battery. Save your money.Original OEM battery. Not refurbished as other indicated. Work great as a back up battery.Tal como lo necesitaba este producto cumple con mi compra