I have two old Shark Freestyles and I like them light and neat in a dog hair cup. Both started behaving, ran for 3-5 seconds then shut off even though they were fully charged. Suspecting the battery I bought one of these, charged it and tried both and the vacuums are fine now so I ordered a second battery. OEM battery, we'll see. Another tip for old sharks: when you take the brush out to clean, take out the white bushings, clean the underside and grease with silicone. The brush should spin freely, mine didn't spin, but everything works better after good care.