Gas Spring for IRB4400 Referencia: 3HAC8578-1 Intercambio: E3HAC8578-1 For IRB4400 robots from M94A to M98, except FS versions. From M98A, IRB4400 robots are equipped with a hydraulic spring 3HAC15083-1 , 3HAC6015-1 or 3HAC3702-1. Previous compatible references : 3HAC0289-1 3HAC1058-1 3HAC1232-1 3HAC1233-1