They’re actually a bit different.

Let’s talk about the bar end plugs from Nitto.

Bar end plugs are those small plugs for the handlebar ends. Nitto produces two different types of bar end plugs.

The biggest difference between the two are the diameters of the bushings, but the outer diameter of the plugs are actually slightly different as well.

Let’s take a look at the ones with the blue bushings first.
These are the ones with 23.8mm outer diameter. They are exactly the same diameter as the bar ends of drop bars.

Now look at the ones with black bushings.
These are the types with 22.2mm outer diameters. They’re exactly the same size of flat bars and sweep bar ends.

So, if you’re running a drop, pick the blues and if you are running flats or sweep bars, go for the blacks.