Hex lag bolts (or screws) are used in timber construction, they are essentially an over sized wood screw. Lag bolts are also used in the marine industry and in railroad and bridge construction. 

We stock: 1/2″, 3/4″, 5/8″ diameters up to 28″ in length

All lag bolts over 10″ in length are only stocked in even lengths, anything uneven would be a custom order