Watch out for connectors that are too tight or the incorrect size!Huh? What does that mean? The female connectors on this battery replacement are either too tight or too small. Also possibly the ramp section of the female connector is not sloped properly. In any case, it is an issue.So what's the issue? There is a danger that because of the tightness or size issue of the metallic female connectors on the battery, the metallic male connectors that are attached to the black and red wires, which are soldered to the headset may get pushed out of their plastic retainers. Watch out for this, as it may lead one to believe the battery is defective (this is bad for the buyer and seller).Other than that, it's a fine product. And the issue I experienced could be limited to the item I got and not affect any other battery they have in stock. It's such a tight tolerance that even if the connector is a little bit off, it will cause this issue.Anyway, the point is to be observant and check the metal connector attached to the headset and make sure it hasn't been pushed out of its plastic retainer. If it has, my solution was to use an Exacto Knife (a very fine pointed blade) to push the metal connector back into its housing. Any small sharp object should suffice (be careful not to stab yourself as everything is very small and it's easy to slip).Shouldn't have put up with my headset dying so quickly for so long. Replacement batteries were VERY inexpensive and VERY easy to install.Bought this as a replacement battery for a Savi W720. Battery is slightly bigger than original but still fit. The longer power cord makes it easier to install. Capacity is good. I've been on 2.5hr+ calls without any issues.This battery is a good replacement for the Plantronics brand. it brought new life to my work headset. Talk time was starting to become unusable as the old battery wore out. replacing it with this brought back the ability to wear the headset all day without recharging.They do not charge at all. The connector just barely fits. Not worth. Contact the vendor for your device directly because these cheap replacements don't even work.ValueA Little to large for my CS55 head set.It worked as described