Electrical adapter box within improved fastening structure

An electrical adaptor box comprising:

• a main body defining a space with at least one connector mounted therein;
• a cover sub-assembly including a lower cover and an upper cover, said lower cover directly mounted unto the main body and defining a first opening upwardly exposing said connector, said upper cover directly mounted unto the lower cover and defining a second opening essentially aligned with the first opening so as to upwardly expose said connector;
• a fastening element supported upon the main body with an up-and-down moveable pushing portion upwardly exposed upon the lower cover and a reliable latching portion latchably engaged with the upper cover;
• wherein downward pushing the pushing portion may release the latching portion from the upper cover so as to allow upward movement of said upper cover away from the lower cover.