Featuring a 1/2" square drive, it fits perfectly in the following sizes: 11/16" (17mm) - 3/4" (19mm), 13/16" (21mm) - 7/8" (22mm), 15/16" (24mm) - 1" (25mm) and 1-1/32" (26mm) - 1-1/16" (27mm).
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