PC +4 / -1 Vampiric Bow Mod

Hi, this is actually my first time seeing a bow mod +4/ -1
I tried wiki under inscription couldn't find anything talking about it

so i was wondering if it's worth anything or merchant

It's not an inscription, it's a Bow String.
Since +5/-1 is max, merch it. Even the max version is less than 1k.

merch

its not old/nerf'd, you can still get them