Thread Size M12x1,25x224,5. Elring Cylinder Head Bolt Set. OPEL: 55 571 177 OPEL: 55 571 777 (10x) OPEL: 56 07 692 OPEL: 56 07 692 (10x). Why Choose Elring?. Bolt Head-/Nut Design Female Torx. Check your vehicle's specifications match the compatibility list below.
