These are Grade 5 Titanium washers for all bolt in M8, M10, & M12 diameter bolts
10mm hex head takes M6 washer
(Left side)
12mm hex head takes M8 washer
14mm hex head takes M10 washer
17mm hex head takes M12 washer
Available in different thicknesses
Only the m6 washer is recessed for their bolt/nut