Potion flask

The Potion flask was announced in the 2012 February Behind the scenes. To make it, players must have a glassblowing pipe and 89 Crafting (boostable) to make the robust glass. The flask holds up to 6 decanted doses of a potion and will shatter upon being emptied of its contents, and despite being created entirely of non-tradeable materials, the flask and any fully filled flasks is able to be traded. Because the resources required to craft Robust glass are non-tradeable and have a maximum of 50 available to players daily, Potion flasks will likely be in short supply as well as high in demand, and it is Jagex's hope that players will find making them profitable. Also, making the flasks out of Robust Glass is un-assistable. Making the the Potion flask gives 100 crafting xp and 70 mining xp in total of 3,500 mining and 5,000 crafting xp daily.

Unless a flask is completely full, the flask is untradable.