pretensioner rear seatbelts?

[Adam D]

Bought some black rear seatbelts and just thought nothing of them when i got them, they have the pretensioner on them and a little wire. Presuming this has something to do with higher spec models such the 1*2 etc.. Anyway i went to have a look at changing them over in my 1.2 and see that the ones i have in are not pretensioned ones and the new ones i had wouldn't even fit in the space!

Have i wasted my money with these? The only reason i bought them was because the seatbelts currently in are silver and look grubby.

Thanks