I bought this Warning Triangle in Aug 2012 and put it in the trunk lid drop down tray of my 2012 BMW 550i. It has been there until today, thankfully I have not had a reason to use it.
Today, Oct 2014 I opened the trunk to find metal dust on the trunk mat. The Warning Triangle hollow plastic base had developed a crack at one end, opposite to the end with the cap. The 3 lb of metal dust which the base is filled with to give it weight was pouring out into the trunk tray and then onto the mat when the lid was opened. What a mess!
I can only surmise that the heat inside the trunk on hot summer days caused the plastic base to split. Pretty poor quality if this is a genuine BMW part.