The mahogany jib block goes under the cheek block for the on deck jib sheet cleating system.  The block comes in two sizes:

3″ x 5″ x 3/4″ for jib cleating systems where the jib sheet comes across the cockpit and cleats on the weather rail

3″ x 5″ x 1-1/8″ for jib cleating systems where the jib sheet cleats on the leeward rail (This is the standard rigging configuration for the daysailing Flying Scots as well as Flying Scots that were rigged with the Basic Racing Package)

The differences in the block thicknesses are due to the cleating angles so that the jib sheet cleats and uncleats easily.  Please select your desired block thickness below.