| 摘要 |
<p>The present invention provides a fastener whose torque-receiving circumference is either circular or polygonal with more than twelve angles. In order to manipulate such a fastener, a wrench and a socket for a socket wrench have a housing (510) having an interior space, and a fastening unit disposed in the interior space of the housing, wherein the fastening unit (530) comprises a plurality of sprags (540) and ends of the sprags each protrude toward the interior space of the housing forming an arc, are provided.</p> |
