Stahlwille series 13 combination spanners metric sizes with 15 offset ring end they are drop forged from high grade chrome alloy steel and chrome plated manufactured to din 3113 form aiso 7738 form a 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 stahlwilless double t profile stahlwilles unique plating method prevents the problem of chrome flaking the ring end o