High Strength Bolts normally means the bolts quenched and tempered after sizing. Which give more pressure resist. ItemHigh strength HDG Hex bolts and nuts MaterialCarbon Steel BrandR from Hebei Jinan Thread typeHex thread SizeM12-M30 Length(mm)30-200 GradeClass 8.8/10.9/12.9 FinishHDG/ Black/dacromet StandardDIN6914 Screw ThreadM12M16M20M22M24M27M30M36 d PPitch1.7522.52.5333.54 bmax2328333437394250 min2126313234374048 dsmax12.716.720.8422.8424.8427.8430.8437 min11.315.319.1621.1623.1626.1629.1635 kmax8.4510.7513.914.915.917.920.0524.05 min7.559.2512.113.114.116.117.9521.95 smax2227323641465060 min21.1626.16313540454958.8 Packaging & Delivery Carton size26X26X13mm Carton Gross weight25.00 kg pallet size80x100cm Package typebulk in plastic bag of Carton box on Wood pallet 3 or 4 layers Lead Timein stock or negotiable date Certification of Quality Guarantee CE Certified Valid from 2019-01-29 until 2024-01-28 ISO9001-2015 Valid from 2018-04-20 until 2021-03-30 China High Strength Fasteners website:http://www.jn-fastener.com/high-strength-fasteners/