The PK124K Battery Backup Kit provides continuous battery charging so that if power to system equipment is interrupted, standby operating power is provided for up to approximately 6 hours. (Time may vary depending on system size and usage.) The PK124K kit includes a transformer, a battery charger and two batteries—all preinstalled in a 19-gauge cold-rolled steel housing. Knockouts are included on all sides except the lid, to allow connection of electrical conduit from any direction. In addition, the lid has a knockout which can be used to install an optional key lock. The enclosed single-gang electrical junction box is galvanized steel with a stainless steel cover plate. TekTone systems supported by the PK124K include the DS100 Door Sentry & Emergency Alarm System, the CM800 Emergency Call System, Tek-ENTRY Apartment Entry Systems, and the Tek-SAFE Area of Rescue Assistance System.