The most essential item in each archer's gear is his backpack companion called Ava's Device. The device will automatically take items from below for you. If you're planning on increasing your Ranged ability and are using expensive ammunition, this item is a must-have.
Ava's Devices offer the best benefits to Ranged skill from all slots in the cape, they are able to save both money and time due to automatic pickups. In addition, they may also attract random junk into your inventory. You can obtain this item by finishing Animal Magnetism quest which requires the completion of Priest in Peril, Ernest the Chicken and Restless Ghost quests. Additionally, you'll need levels 18 Slayer 19 Crafting, level 18 Slayer, 30 Woodcutting and Ranged. There are three kinds of tools which you can buy.
Avas Attractor : If you are less than level 50 in your Ranged skills, you'll get this as a reward of the quest. This piece of equipment automatically absorbs 60% of the ammunition you carry. The 20% that it breaks (which is the norm for all types of ammunition) and the remaining 20 percent of it ends up on the floor. It also gives you a +2 bonus to your accuracy in the Range.
Avas Accumulator Level 50, if your already have an Attractor then you can go to Ava to upgrade the Attractor by giving her 75 steel arrows and 1000 gold. However, if you have successfully completed the quest after reaching 50 Ranged, you'll be able to get the upgraded version immediately, without any additional costs. The upgraded version increases the its rate of ammunition collection from 60% to 72 percent. The upgraded backpack also comes with +4 Magic Defence and +4 bonus to Ranged Accuracy rating.