This blok is used to fill in some space in your system and provide some additional stability to the grid.  These are great to blend underneath other tools like extensions and ratchets. 
 
Available is a 1 inch version primarily for all extension types and 1/4" Drive Ratchets, the 1.5 inch version is good for 3/8" and 1/2" Ratchets.  
 
They can be used in other ways to provide borders around areas to section them off, but those wouldn't be the best use of space in a drawer but do provide to the overall aesthetic appeal of a full drawer layout.  
 
Note:  We recommend removing the drawer liner to give the Bloks to strongest bond in your drawer possible.