Fixed angle extension for a tool

An extension to be releasably engaged with a driving tool and a driven tool, comprising:

• a first tubular housing for accommodating a first beveled gear, a first shaft intersecting via the first beveled gear and having a first shaft end at one end thereof for engaging with one of the driving tool and the driven tool, and a first pair of supporting bearings for rotatively supporting the first shaft in the first housing;
• a second tubular housing for accommodating a second beveled gear, a second shaft intersecting via the second beveled gear and having a second shaft end at one end thereof for engaging with the other one of the driving tool and the driven tool, and, a second pair of supporting bearings for rotatively supporting the second shaft in the second housing;
• and
• an internal end thread in one of the housings and a threaded locking ring at a side of the other of the housing being releasably engaged in a L-shape or T-shape,
• wherein the first beveled gear is positioned at another end of the first shaft to rotatively engage at a non-zero and non-180-degree angle with the second beveled gear, positioned in the medium section of or at another end of the second shaft.