which exhaust donut for 1999?

[hybridx]

I have a stock exhaust on my ex motor ... on 1 end of the a-pipe are 2 flange rings that go to the exhaust mani; I need 1 on the other side of the a-pipe that goes to the catalyst, a 1 gasket/donut.

Honda says this piece is either-

p/n 18229-s01-x01 (45 mm In.diameter x 58 mm outer dia.) or
p/n 18229-s01-x11 ( 51 mm I.D. x 64 mm O.D.).

Anyone know which is it?
Thanx Much,

[hybridx]

btw Don't ask to use/compare it to the old 1 ... there never was an old gasket.