These are a DIN 985. Further details are as follows 'T Type' Nyloc Nut Across the Flats (A/F) - 5.5mm. 'T Type' Nyloc Nut Height - 4mm. 'T Type' Nyloc Nut Across the Flats (A/F) - 7mm. 'T Type' Nyloc Nut Height - 5mm.
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