To Suit Elettrika & Cisa Rim Locks. This Cisa booster is and electronic circuit that enables additional functions for a connected Cisa Elettrika locking device. Booster can also be installed on other Cisa electric rim locks and adds the following functions: Voltage adaptor function - adjust to 12Vdc, 24 Vac, 24Vdc Undersized power supply Reduced input Electric hold open function . Fits directly to an Elettrika frame - sits beneath the case cover without impairing product appearance. Supplied with fitting instructions and fixing screws. Can be installed with other Cisa rim locks and needs to be positioned as close as possible to the lock.