While I’m on an Assassin’s Creed prop replica posting roll, check out the Ezio Smoke Grenade Prop Replica from Museum Replicas.
Based on the smoke grenade from Assassin’s Creed II, this masterful, non-working Assassin’s Creed Smoke Grenade Replica is made of metal.
It also features a removable center arming mechanism which you can see removed in the following image:
Measures 2 3/4-inches in diameter.
You can get these via Amazon and via Ebay for $44.99, but the cheapest price is by far at Entertainment Earth for $35.99 at the link below: