Sturmey-Archer 22T-1/8” Splined Cog
Don't sneer at old 3-speeds. They are serious bikes, built for serious use. - Sheldon Brown.
I have fallen in love with vintage 3-Speeds. You really don't need more than that. I am especially fond of Raleigh's with a Sturmey-Archer AW hub. These work horses are nearly indestructible, easy to maintain and operate flawlessly. The only drawback is that the original cog was 18T on most, resulting in gearing that was too high (hard) for the average mortal. This is remedied by replacing it with a 22T one. These cogs are authentic Sturmey-Archer and can be installed easily by someone with a little mechanical inclination or your local bike shop. Vive les trois vitesses!