I purchased one of these to replace my aged BR1000. I thought I would go up in capacity/runtime, and this unit is of identical form factor = no rearranging my desk. However the internals are different and this unit makes a very audible (not loud, but audible) hum from the charging circuit, whether on or off. I will be returning it and likely getting a battery for my BR1000, because the hum is going to drive me nuts.