Apr. 1, 2015. TDK Corporation has announced that its Hong Kong-based HDD head manufacturing wholly owned subsidiary, SAE Magnetics (H.K.) Ltd.
You use a wrench to screw, or unscrew a bolt. A screwdriver is for screws. Either way you turn it left. Some bolts have reverse threads and would turn the other way to unbolt.
1 Using the spark plug ratchet, begin unscrewing the plug by turning counterclockwise. Once the plug is loose enough, finish by removing it by hand.  Before inserting the new spark plug into the valve, use the gap gauge to calculate a proper gap.