Abstract: A seal head assembly includes a case. A ferrule is seated against the case. A spring is seated at one end against the ferrule. A spring seat receives a second end of the spring. The retainer ring has a band and a plurality of tabs, wherein the band engages the spring seat. A metal bellows has a first end in contact with the case and a second end having a contact surface for the tabs of the retainer ring. A seal washer has an annular groove, wherein the seal washer is received in the second end of the metal bellows. A seal is received in the annular groove of the seal washer.