I know that starters and starter sockets interface with mushroom-shaped pins that twist 90-ish degrees to lock. I also know that some bulb bases (specifically GU-24 and GU-10) use the same mechanism. I know that GU-24 is definitely way to big to be the same as a starter socket, but GU-10 (from the pictures I have seen) looks promising in terms of size.

Are these bases the same? GU-10 sockets are a lot easier to find than genuine starter sockets, and if I can use them that would be great.

Thanks!

no

Darn, I thought they may have looked a little small. That is unfortunate.
 

Starters have a dedicated sockets for them, which don't have a name. It is neither GU24 and GU10 lamp sockets.
Starter sockets are universal worldwide except some Japanese glow starters which have a screw base socket.

Starter sockets are universal worldwide except some Japanese glow starters which have a screw base socket.

Yea I have seen those, I think they are cooler-looking than the normal ones.

@Multisubject are you kidding starter sockets are hard to find?? Tons are available all over the world, literally new and used.

Yea there are a heck of a lot of them, but none of them are as recessed as I would like them. I need some variety. Many are snap-in style (eww), and some are just plain ugly or cheap.

The starter socket itself isn't recessed. It can be recessed into the fixture, but not by itself.

Some starter sockets are indeed recessed by themselves, they mount directly to the enclosure and have a cavity for the starter to sit recessed.

Starters have a dedicated sockets for them, which don't have a name. It is neither GU24 and GU10 lamp sockets.
Starter sockets are universal worldwide except some Japanese glow starters which have a screw base socket.

Although most countries in the world do not give a name for the standard 2 pin starter sockets, I am aware that Japan actually calls those 2 pin starters sockets “P21” sockets. Evidence for the starter sockets being called the P21 base can be found on the specification sheets for Japanese starters with the standard 2 pin base.

See here:

https://www.seiwa.co.jp/en/product/ie/pdf/Lamps.pdf

https://www.akaricenter.com/chokkan/grrow/pdf/mitsubishi-fg-4p.pdf

https://kyowadenco.co.jp/wordpress/wp-content/uploads/fl-types.pdf

This basically means that standard 2 pin starters use the P21 base just so you all know.

However, every now and then, there are some starters that have a larger variant of the 2 pin starter base. For example, the starters used in North American F90T17/F100T17 preheat fluorescent fixtures use those larger bases. Additionally, there were some early 4 pin thermal starters that had a similar pin spacing to the F90T17/F100T17 starters with the addition of two other pins. It still holds true that P21 base fluorescent starters are used in virtually every country in the world.