SOLID CARBIDE Door Lite Bit for Fiberglass Doors:

Made from solid carbide, each bit contains up and down cut flutes. This flute design creates a compression cut that prevents fraying and splintering. Designed specifically for fiberglass (not steel) doors. Cut up to 600 door lite cut-outs/bit! Aribell Part #:UD5222 Shank Diameter:  ½”; Cutting Diameter: ½” & Cutting Length: 2 ¼”; Overall Length: 5 ½”