From Ebay

"Shimano
twin power 2500 Reel


Boxed. New article

● An AR - C spool： An AR - C spool is the epoch-making spool
shape that overturned common sense of conventional spool shape.

If conventional spool shape pursued Driving distance,

it was done when "order taper shape" attached great importance
to a trouble reply well if "a reverse taper" was good.

It is a newly-designed "AR - C spool" that was born to achieve
an important purpose in these two casting at the same time.

AR - C spool ring before spool, special form is, and release of
a line is fixed in the best state in the cast by this effect.

I achieve a trouble reply without sacrificing

Driving distance by this "line rectification effect".

I confirm shape of a spool ring by a casting test of tens of
thousands of times, and it is it in the shape that realized that

I reduce reducing resistance of line release in casting and a line trouble ideally."