Arrow 591189BL 5/16-Inch by 5/16-Inch Arrows Black T59 Insulated Staples, 300-Pack
Arrow's Insulated Staples are intended for use with the T59 Wiring Tacker.  These black staples, which are 5/16-inch high by 5/16-inch wide, are for use with wires up to 5/16-inch.