Now I just got this one ?

Mystical tanned mountain map
Use Item to Receive Effect

Quantity: 4
+1% Guild Point
+2% Stealth

But at what lvl does it not gives me exp anymore ?

Same tiers as Leather - https://ladderslasher.d2jsp.org/index.php?g=14#Leather

And iirc tier 1 is up to level 15 and then +5 level per tier

your map -> max monster lvl 25
less exp after lvl 25

This post was edited by Razo on Sep 15 2018 08:39am

That was something I did understand thanks

Other than reduced experience using a character higher leve, you also get reduced drops.
Example: Using a level 40 character on a Patched Map

Note: That is if it is the killing blow, so you can map with others that are level 14 as an example, and they do the final hit, drops would be normal.