If you want perfectly flush joint lines for your stile and rail doors, setting the proper router bit height is essential. Even the slightest misalignment can mean significantly more sanding time after the doors are assembled. These setup blocks make setting the height easy. Simply set the block on the table and raise your router bit until the profile is lined up perfectly with the profile in the block. One side of each block is machined for stiles, the other for rails, meaning you'll never have to dig around for a matched pair. Features: Set your stile and rail router bits to the precise height, every time!Simply raise the router bit through the table and align it with the profile on the blockRail cut on one side and stile cut on the opposing side