Default PDF Reader on Sony SmartWatch 2

Hi folks,
i think i'm going to buy a Sony SmartWatch 2 and i would like to know if there is a good PDF reader for it. I know that the screen of the smartwatch it's very small but i will need just a preview of the pdf. I already saw the app on the play store but from the review seems that it's not the best. I would like to know if you guys had some experience with that.
Thanks in advance...