American SHAR FA.2 with none standard ejection seat…?

Hey guys,

Just been watching the US Sea Harrier FA.2 and noticed that it had a different ejection seat from the standard one. What would be the reason for this?

http://www.youtube.com/watch?v=0roV1yql_D0&playnext_from=TL&videos=E7lM1fcdj_0&feature=grec_index

Regards,

Phil.