How big persimilis mites?!smaller than theyr prey?

[Strudel]

I just bought persimilis predatory mites from a well know company,

But seems to me they are more little than spider mites they have to kill

Is strange as is written everywhere that they are bigger
Can be possible that they sell predatory mites that are not jet in adult stage?
I ask them and they said they are adult...,.

So really do not know what to think.are they smaller than their prey?!?