Exhaust spring

[Bettybeamer]

Picked up my bike today after having Austin racing arcs fitted sounds sweet.they said one of my exhaust springs is a bit loose.what size would This be its the one then goes from y piece to link pipe. Have looked on flea bay so many sizes to pick from.

 

[RossHarper]

if it's from the Y to link, is there not another on the other side of the Y that you could take off and measure? (some have 2 springs, unsure what the ARCS system is like)