Dyson was out of replacement batteries, so I thought I'd try this knock off. Installation was easy and I appreciate the extra battery life.The best feature is that I can now pull the trigger twice and the vacuum just stays on. I know longer have to keep holding down the button for longer cleaning sessions. It's much easier on my finger. This should really be a factory option on all Dyson vacuums.It's been three months and the battery life is still excellent. The only issue I've noticed is that it is a little difficult to get the vacuum out of the charger. I still think it's worth it for the extra power and double click on/off.