M5 M6 M8 Socket Shoulder Bolts - 12.9 High Tensile - Hex Allen Key Screws HT
These are an ISO 7379. For example8mm - M6 x 20mm. Thread Size - M5 (5mm). Thread Size - M6 (6mm). Thread Size - M8 (8mm). The Sizing of the Shoulder Bolts is explained here Allen Key Size - 3mm. Flanged Hex Head Bolts.