Newbie in need of PC :o

hiii, I'm new to gw and the whole selling items things, here are a few things i need help with~ also can anyone tell me what a "-2/-2" is? or why a r10 tact shield -2/-2 is worth 30e?

1. r9 Marksmanship- Shadow Bow
15-28
poison duration 33%
armor +5

2. r8 shadow bow
14-26

Both are merch food.
Also -2/-2 don't drop anymore, thus the value, for usefullness and rarity.

Double check your bows for damage mods if there are no mods like 15^50 or +5energy or 15% -1 health they are prob merchantable. The r8 shadow may interest a collector or 2 around here, but not for much.

Generally -2 -2 means -2 physical damage while enchanted + -2 physical damage while in stance. There's also the less desired -2 -3 which means one of those and -3 physical damage while hexed (sometimes theres -2 while hexed, but that brings the value down quite a bit).

thank you~ 12 characters