Darby Gates Glidden Drills are side cutting instruments with safety tips. They should be used at 750-1500 rpm. They can be used with both crowns down as well as step back fashion. It is used to remove the lingual shoulder during access cavity preparation and to enlarge the canal orifice. Not only are these instruments good for making post-holes but they are exceptionally good for preparing root canals in an easy and reliable manner. They are especially good to use in a modified crown-down technique. R.A type. Features and Benefits Side cutting For cavity prep Easy and reliable to use Exceptional for root canal prepping