Stahlwille Series 20a Double Ended Ring Spanners. AF imperial, drop forged from high-grade special steels and chrome plated. The spanners are optimally hardened in continuous furnaces with no scale build-up or skin decarburisation and gently quenched in oil. They are extremely strong yet lightweight due to Stahlwille\'s \'double-T profile\'. The unique plating method prevents the problem of chrome flaking. The ring end of the spanners are equipped with an Anti-Slip Drive profile to permit high transmission of forces to the flats of the nuts and bolts without damaging them. MADE IN GERMANY.Stahlwille Double Ended Ring Spanner. Size: 1/4 x 5/16 AF.Length: 180mm.