A security latch for a double gate or door includes:. The system comprises a proxy server configured for receiving requests for content from requesting end user browsers and fetching the content from content provider servers over at least one communication network. The first transistor further includes a first metal gate and a protecting layer covering sidewalls of the first metal gate. There are also a plurality of receiving fixtures on the base each one for receiving an end of one of the plurality of burster tubes. The transmitter is constructed to use only a small amount of power which, preferably, is supplied by one or two low voltage replaceable andor rechargeable batteries. An active compensation of at least one portion of at least one imaging aberration induced by the change in the focus positions during the exposure time interval has the effect that the imaging quality is not significantly impaired by the alteration of the focusing during the exposure time interval.