What I am not understanding is that it is an off-hand counterpart to the spider wand RuneScape Gold. It lets users cast spells using the offhand slot. What exactly does this mean and should I consider using it? Furthermore, I don’t understand what “off-hand slot” is.

Well as I’m sure you’ve noticed players can dual wield weapons nowadays. In the past (as in pre-Evolution of Combat) other than 2 handed weapons your only options were to use a one handed weapon with the use of a shield or perhaps an offensive shield slot item such as the Defender (or a God book, but they were still shields in theory. So now you have an extra choice – you can wield a weapon and a shield for extra defensive bonuses (and can use a couple shield only defensive/constitution abilities) or you can dual wield weapons.

Dual wielding is more offensively focused clearly, and it’s superior to using weapons with two hands because you’ll have better capabilities. This is why the majority of people would rather use dual crossbows than a 2handed crossbow or bow, or using a wand with the shield slot offensive weapon equivalent (usually orbs, like Spider Orbs) Spider Orb) rather than staves (except in certain situations where you must risk just one of the items). The basic idea is to think of the orb as a type of sword or crossbow that’s offhand, even though it’s not designed like weapons.

Thus, it’s the equivalent that of Spider Wand because it has the same tier, and it’s the offensive weapon that is matched to the off-hand in the Spider Wand. And it let’s the player use spells using the off-hand slot because it counts as a weaponjust as having two swords, for example, it would be possible to deal the damage using both. If you’re at the level Old School RuneScape Gold, you could most likely buy and carry Batwing as well, which is even better and cost-effective too.