This is a titanium M10 x 1 nyloc hex flange nut that has been fully CnC machined with rolled threads and is a fraction of the weight of the standard steel bolts while maintaining the same strength characteristics.

10mm High
14mm Spanner
19mm Flange

Also corrosion resistant so will not rust and will continue to look good and give excellent service for years to come.

Always Torque to between 80%-100% of manufacturers recommendations.