Sentence: What size towels do you need?

[Sweetpumpkin]

Hello,

I have a question on the sentence below:

"What size towels do you need?"

I think 'of' should be inserted between 'size' and 'towels'. If not, is 'what size towels' a common expressions?

Thanks,
sweetpumpkin

[Kitosdad]

Good morning SP,

'is what size towels' a common expressions? Only when buying them in a store, or ordering from the reception when staying in an hotel and asking for more.

Face towel, hand towel and bath towel.

" of " can be optionally used.

Kitosdad.
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