I believe they are nylon cased. When I installed my W124 joints they were really packed with a similar but brown tinged grease. These ones are not and they have black rubber boots too unlike the w124 ones which were some sort of plastic ones.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)