Which stickers can I use during FMC?

I'm interested in FMC currently.. (sub30 completed )
But i don't know which stickers can be officially used during FMC, as the regulation doesn't mention about it.
I'm using round / green / numbered sticker now.

So my questions are:
1. Shape & Size : round, square, ...
2. Color : single-colored or not
3. Text : prohibited or not
4. other restrictions?

The WCA regulations say: "Coloured stickers". So I guess any size, shape (ect.) I don't know what you mean by "single-colored" but only one colour would be allowed on one sticker No text allowed (numbers ect.)

Hope this helps.

(Source: https://www.worldcubeassociation.org/regulations/#E3c)

JasonDL13 said:

No text allowed (numbers ect.)

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But you are allowed to bring a pen, so you can write numbers on the stickers as soon as the event starts

dbax0999 said:

But you are allowed to bring a pen, so you can write numbers on the stickers as soon as the event starts

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no

Where do you get "No text allowed" from? I've personally pre-marked stickers (even in front of the delegate) and seen people use them.

It's a bit unclear in the regulations, but you are usually allowed to use pre-marked stickers and your own pens. Of course you may not write complete algorithms on these stickers beforehand, or something like that.