7Mark bolt(Full thread(Coarse Steel Trivalent white(Silver) 6 X 15 Pitch 1.0

These are S45C bolts with a strength class of 8.8T, marked with either "7" or "8" on the head.
They feature a regular hexagonal head and are tightened using a wrench or spanner.
They can be tightened more securely than slotted or cross recessed screws.
Full thread = A bolt where the entire length from the hex head to the tip is threaded.
Partial thread (medium bolt) = A bolt that is threaded from the tip partway up the shank.
Partial thread length calculation (approximate guide):
L = up to 129     Nominal thread diameter × 2 + 6
L = 130 to 219   Nominal thread diameter × 2 + 12
L = 220 and above   Nominal thread diameter × 2 + 25
Example: For an M10×250 partial thread bolt, since L (length) is 220 or greater, the thread length is 10×2+25 = 45mm.
Thread Pitch & Hex Width Across Flats List　Hex Bolt Encyclopedia

• 7 Mark bolt Full thread Coarse pitch
• Nominal thread diameter M6
• Pitch 1.0
• Length under head (ℓ) 15.0
• Head height (K) Nominal 4.0 Tolerance ±0.25
• Width across flats (S) Nominal 10 Tolerance 0,-0.6