The 21 Piece Wiha Insulated 1/4in Ratchet Wrench Set is for safe installation of terminals and sleeves, conductor connections and fastening of conductor lines. The nut driver and extensions are mechanically locked, the change is initiated by pressing the activation button once.Each tool in the set is subject to an individual piece testing, as per the international IEC 60900 standard, allowing users to work safely on live parts up to 1,000 V AC. Organized and neatly stored in a practical and sturdy case. Contains the following: 1 x 1/4in Insulated Ratchet Wrench with integrated switching lever allows effortless switching between right and left rotation. 2 x 1/4in Insulated Extensions: 75 & 150mm. 12 x 42mm 1/4in Insulated Nut Driver Inserts:  4.0, 5.0, 5.55, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0 & 14.0mm. 5 x 65mm 1/4in Insulated Nut Driver Inserts: 3.0, 4.0, 5.0, 6.0 & 8.0mm.Additional Information:Type: Socket Set