Created by e621
Features:
You need an alt / friend to do this
Steps:
-> Step 1: Get your friend/alt to send you a trade, or send a friend to him.
-> Step 2: On the trade menu, put all the items you want to dupe, but dont accept yet
-> Step 3: When you have all the items on the menu, accept on the account that is receiving the items
-> Step 4: Now that the other account accepted, execute the script (as many times as you want, more times = more items)
-> Step 5: Wait a bit (20 seconds or more) And check your inventory
-> Step 6: Profit. 
game:GetService("ReplicatedStorage","Dupe").tradePlayerReady:FireServer(true)
game:GetService("ReplicatedStorage","Dupe").tradePlayerReady:FireServer(true)