RB6 rear arms to RB5

[fastfilli]

Having seen Kev Lee running RB5 (UM566) rear arms on his RB6 on Tuesday I thought I would give them a go too.

Not sure why as my car is fine but I like to fiddle

So I ordered some arms only to find they come with 1 front arm and 1 rear Fail LOL, and they dont look the same as what a seen on Kevs LOL.

Any way my question is whats the difference between UM566 rear arms and UM521-1 rear arms ?

Kev Lee = UM566
Atsushi Hara = UM5211

They look the same to me?