Genuine Y4REK 

8mm (5/16") x 50mm strong screw Holder for Stainless Steel Tek screws hex head Bit Nut Driver

High quality nutsetter out of stainless steel for hexagon head screws. 

Stainless to prevent the risk of extraneous rust. 

Non-magnetic design with retaining spring. 

1/4" hexagon hex drive.