This is a quality grade 5 hex head bolt assortment kit that includes the most popular sizes. This kit contains: 10 pieces of each hex bolt size: 1/4-20x1/2, 1/4-20 x 3/4, 1/4-20 x 1, 1/4-20x1-1/2, 5/16-18x3/4, 5/16-18x1, 5/16-18x1-1/2, 5/16-18x2, 3/8-16x3/4, 3/8-16x1, 3/-16x1-1/2 and 5pcs of a 3/8-16x2. 30 pieces of each hex nut size: 1/4-20, 5/16-18 & 3/8-16. 20 pieces of each lock nut size: 1/4-20, 5/16-18 & 3/8-16. 40 pieces of each flat washer size: 1/4, 5/16 & 3/8. 30 pieces of eac lock washer size: 1/4, 5/16 & 3/8. 1pc Tuff Storage Container. 475 pieces in all! Now includes a Free Nut Bolt size gauge (a $8 value)