Hi uncle dave. Picking up my presonus eris 4.5 . What cables do i need to connect it to the pa4x? What should i ask for? Thanks.

Exciting! New speakers for the holidays! The Eris speakers can take 1/4" balanced cables, so get the length that works best for your setup. You really don't need Mogami, or Monster type cables, but stay away from the cheapos with molded ends. (Hosa)
Any high quality, shielded audio cable will be fine. TRS, or TS ... both will work. Buy what's in your budget. Something like this will do fine:
https://www.sweetwater.com/store/detail/QTR10