I didnt want money for it thats why its in the swap section, if i had wanted money for it i would have put it in the sales section but now all the negative points have been raised not much point in thatI think you need to decide what (money) you want for it.
I bought mine for £69 but, with a clearomiser, batteries and charger, OK they were cheap "extras" and were probably worth £20, so my Zmax probably stood me at £49.
I figured, second hand mine was worth £40, but it is "better" than yours as the screen is straight, has the Ego threading and a screw on top cap.
If I wanted another Zmax, I'd feel comfortable offering £30 for yours...............but that's just me.