The Off-hand abyssal crossbow is a very powerful off-hand ranged weapon which requires 75 Ranged to wield. Currently, it can only be found as a drop from the Abyssal dragon, which resides the the center of the Abyssal Area. The weapon can be very handy for players who cannot afford drygore weapons, or do not want to go through the long process of gaining a chaotic weapon. It's not too difficult to get the item as a drop, since entering the room which contains the Abyssal dragon requires 50 Abyssal demon kills (which requires level 85 Slayer) after which the player can keep killing the monster until they run out of food/resources. But the dragon is considerably hard so players won't be able to kill it enough times to get a rare drop each trip.