<p>The Duplex potion has the "you killed two monsters in one" effect. So items that are 100% loot will be doubled, for example unique items from Pits of Inferno bosses (piece of massacre's shell, imperor's trident, etc). Bosstiary's bonus increases the chance of dropping any <strong>equippable </strong>items, but does not double the items.</p><p>Remembering that the Duplex Potion does not work on bosses with a reward system, only those with loot for those who did the most damage, for example the bosses of PoI, Man In The Cave, Dharalion, Fernfang</p>Fernfang</p><p>An example of when I used Bonus and Duplex on Imperor. He gave 2 trident, the duplex effect. The bonus does not affect unique items, only equippable items (crown legs):</p><p><img alt="" src="https://www.tibiaqa.com/?qa=blob&qa_blobid=594744741096365086" style="height:374px; width:600px"></p>