Abstract: A metric and English socket wrench is rotatable about an axis, and includes an inner peripheral surface. The inner peripheral surface has first engaging portions, and second engaging portions arranged alternately with the first engaging portions. Each of the first engaging portions has two first engaging surfaces interconnected to form a V-shape. A first apex is disposed between the two first engaging surfaces, and is spaced apart from the axis by a first distance. Each of the second engaging portions has two second engaging surfaces interconnected to form a V-shape. A second apex is disposed between the two second engaging surface, and is spaced apart from the axis by a second distance. Ratio of the first distance to the second distance is more than 0.94 and less than 1.06.

Abstract: A clutch includes a drive body disposed in a hollow base and having a plurality of force-bearing surfaces each cooperating with the hollow base to define an accommodating space therebetween. A clutching component is received in the accommodating space, and abuts against the hollow base and the force-bearing surface at first and second contact points, respectively. An angle between two lines, passing respectively through the first and second contact points and intersecting at a center of the clutching component, is greater than 160° and smaller than 180°. A ratio of a maximum distance between the inner annular surface and the force-bearing surface to a cross-sectional dimension of the clutching component is greater than 1 and smaller than 1.1.