Set contains every socket in our 1/4" Surface Drive line; plus 3 extensions; universal joint; 1/4" F x 3/8" M adapter and 1/4" Hex x 1/4 M adapter. Fractional sizes 3/16" to 9/16" and Metric sizes 4mm to 15mm. Universal sizes 1/4" to 9/16" and 5mm to 15mm.