Philips M3538A battery for Philips MRX defibrillator / monitor. Came included with the MRX I bought, which was sold as preowned, having been purchased by the seller in a job lot following 18 months storage. Appears completely dead, I can’t seem to get it working so am buying a brand new unopened battery instead. Maybe possible to recondition for electrical engineering type people but I don’t understand it enough to risk messing around. No warranty offered or implied - it should be assumed this unit is faulty.
eBay