First of all, the hinges they attach to are steel, not plastic as others here say. A generic untitled brown box from China fits perfectly under the hood of my 2005 BMW 325CI Cabrolet. Gas filled, Note: I used some silicone paste in the holes on each end to make it easier to slide. You don't have to undo the clip at each end or pull out the clip as shown in the video. You snap your hand. My hood is like new now, easy to lift and hold! Also TOP PRICE!