These Universal Extension Bloks are designed to secure all diameter extensions  1/4" 3/8" and 1/2".  They have magnets embedded inside the Blok strategically positioned to provide grip for the blok to stay put, but also to attract the extension to the blok.  One Blok is sufficient to hold one extension, but an additional blok will provide additional stability for longer extensions over 6-8 inches.
 
The ToolBlok system is designed around using every square inch of your drawer so this Blok takes up one square inch and fits perfectly within the system and can be incorporated with other Bloks.
 
These Bloks can also be utilized to organize screwdrivers and nut drivers, thanks to the embedded magnets they will not go anywhere.  
 
Note:  We recommend removing the drawer liner to give the Bloks to strongest bond in your drawer possible.