Grip Rite Prime Guard GR034HG1M 21 Degree Plastic Strip Round Head Exterior Galvanized Collated Framing Nails, 3-1/4" x 0.131" For best results, use with Grip-Rite GRTFR83 and/or GRTRH350 21 degree round head framing nailers Compatible with most 21 degree round head framing nailers including: Bostitch, dealt, Duo-Fast, Hitachi, Makita, Porter-cable, Ridgid and Senco For use on all exterior applications and with all treated lumber Proprietary polymer coating is equivalent in performance to galvanization that meets ASTM A153, Class D as tested under ICC-ES AC 257 Meets or Exceeds ASTM F1667 (if applicable)