SHS AUG/SIG550 cylinder head, Ver.3

Aluminum cylinder head with longer nozzle pipe for AUG/SIG550 models with Ver. 3 gearbox. The cylinder head also has a double seal to improve tightness. The end that comes inside the cylinder also has a padded rear wall, which the piston head hits. This is intended to reduce the piston stroke and quieten the operation of the mechanism.