vincey / TJB - there is a thread somewhere on here (I can find it later if needed) where I replaced the back-box on my 1.4 MA. I used a brand new one that was advertised for a Bravo. It was an exact and identical fit - for £30 new! I am sure if you are able to look at the T-Jet Sport back system closely you will find its identical too - I cannot guarantee I will add as a caveat - but the 1.4 MA one was.............