Standard brake caliper type

[Paulprior]

Hi
I thought i would fit new seals etc in the calipers while doing my other assorted refurb, i just spoke with Biggred who suggests i have Sierra calipers which could be 54 or 60mm single pistons, as i am away from home for a while and unable to measure them does anyone know the answer for a 95 500?
Thanks
Paul