Hex Shanks have been in demand by many of our customers. They are used to extend the reach of our Roloc Mandrels that come with the Ultimate Sanding Kit (purchased separately). They can be used with the quick coupling feature or chucked in a regular drill chuck. The ends have 1/4 x 20 thread with a lock nut to keep it tight on whatever you fasten it to. Because they are made from plated steel they are very strong and the possibility for flex is eliminated. Please note these hex shanks were made for our Roloc System and do not fit the thread size on the black and white heavy duty pads which are M-6 thread.