6 X Black Tudor style hammered cast iron effect metal door studs

I bought these but never found a use. I've opened it to have a look at one. There's no thread on the shaft as such, just a single groove. Six in pack. Metal construction. Approx dimensions per stud: 17 x 17 mm square stud depth 13 mm shaft length 12 mm shaft diameter 4 mm weight 15 g

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