This governor adjuster e-ring fits:

E3500K1 / E3500 K1 / E 3500 K1 generator

E3500K2 / E3500 K2 / E 3500 K2 generator

ES3500 / ES 3500 generator

ES3500K1 / ES3500 K1 / ES 3500 K1 generator 

ES3500K2 / ES3500 K2 / ES 3500 K2 generator

E4500 / E 4500 generator

E4500K1 / E4500 K1 / E 4500 K1 generator

EMS4000 / EMS 4000 generator

ES4500 / ES 4500 generator

ES4500K1 / ES4500 K1 / ES 4500 K1 generator

This genuine part has been discontinued and is no longer available from Honda 

If you rebuild or restore any type of vehicle you know how important it is to use genuine / original factory / or high quality aftermarket parts. A repair or restoration project is intended to return that power product to as close to original as possible, all the way down to last nut, bolt, cotter pin, cable or governor adjuster e-ring.

If there's even a chance you'll need this/these replacement part(s) in the future you'd better get them NOW!. Keep this in mind,  replacement parts are always good to have. When you decide to sell your Honda power product, including a few extra replacement parts always sweetens the deal for both buyer and seller.