Arachnid Mesh is a unique Spiderweb Sash (notice the pun there?). It is a popular wheel belt due to several of the modifications it has.
The stats:
Defense: 119-138
Minimum Strength: 50
Level Requirement: 80
+90-120% Enhanced Defense (varies)
Slows the target by 10%
+1TB All skills
+20% faster casting speed
Increases maximum mana by 5%
Level 3 poison (11 charges)
Slows the target by 10%
This mod is supposed to reflect the belt’s relationship with spider webs.
Although Arachnid Mesh is more of a launcher belt, this mod only works when melee or attacking with a ranged weapon, so it requires a target.
+1TB All skills
While +1 to all abilities is great for all classes and builds, it benefits casters more, because they have to rely on their abilities to deal damage, compared to melee characters who can rely on strength and the power of their weapons.
A +1 to All Skills not only increases the caster’s Primary Attack Skill by 1 level, but can also enhance any Synergistic Skill, further increasing the power of the Primary Attack Skill.
+20% faster casting speed
This is the mod that every caster wants on their team. Being able to cast spells faster makes a huge difference in the world of Diablo 2, as the faster you can cast your spells, the faster your enemies will die.
Increases maximum mana by 5%
Yet another mod on Arachnid Mesh that is attractive to users. The more mana you have, the better this mod will work.
Level 3 poison (11 charges)
Venom is an assassin skill that deals poison damage. A level 3 poison does 90-110 poison damage.
One thing to note about Venom is that it caps the poison duration at 0.4 seconds. That means if your Abilities and items deal 700 total damage poison over 10 seconds, but you use Poison, you will now only deal 28 damage over 0.4 seconds, and if you want to deal more poison damage, you have to successfully hit to the target again and deal another 28 damage over the next 0.4 seconds. Therefore, Venom prevents poisoning in the long run, and you would have to constantly hit the target every 0.4 seconds to get the full 700 poison damage for 10 seconds.
So while Venom generally does good poison damage, if you want your poison to last longer (and thus prevent monster regeneration rates from rising above 0 for a longer period of time), then you should try to avoid activating Venom or simply avoid items with Venom active.
Resume:
Arachnid Mesh has one drawback: it lacks bonuses to resistances. Otherwise it’s a good wheel strap. It also has a very, very low drop rate, making it hard to find. There are Diablo 2 players who have never seen a web drop in the game. If you’re really excited about getting an Arachnid Mesh for your caster, you might consider doing Mephisto Runs in Hell Difficulty again and again, as Mephisto in Hell seems to have a higher chance to drop Arachnid Mesh (still very, very low though) on comparison to other Bosses and Uniques in the game.