Larco’s G450 controller, part of the Guardian II stand-alone access control system, is ideal for remote, outdoor access control applications, like marina or pool gates. The G450 controller features a heavy-duty aluminum enclosure, and its stand-alone design eliminates the need for a network connection. An ideal solution for pools at apartments or associations, the controller can be configured to grant access only during pool hours. After hours, or if users have been removed from the admit list (for not paying rent/dues), they are denied access. Users carry rugged electronic keys that can go with them, as they go swimming or even scuba diving (to 100 meters).
More info: http://www.Guardian2.com/ledger/