Calculated Kinetics Springfield Armory OSP Hellcat Adapter Plate Black. Adapter plate comes with Full recoil lugs to provide a stable mount. The OEM iron sights are barely useable and recommend using the Ameriglo SA 504 for a proper co witness. Specifications for Calculated Kinetics Springfield Armory OSP Hellcat Adapter Plate: Manufacturer: Calculated Kinetics Color: Black Finish: Hard Anodized Gun Make: Springfield Armory Gun Model: Springfield Armory Hellcat OSP Gun Type: Pistol Fabric/Material: 6061 Aluminum Fit: Holosun 407k/507k/EPS/EPS Carry Red Dot Sights-Footprint: RMSc Attachment Type: Screw Optic Cut: RMSc Cut Weight: 1 oz Condition: New Features of Calculated Kinetics Springfield Armory OSP Hellcat Adapter Plate To Holosun 407K/507K/EPS Carry Package Contents: Calculated Kinetics Springfield Armory OSP Hellcat Adapter Plate Hardware Torx Bit Vibratite Install Card Calculated Kinetics HELLCAT-MRMSC: Springfield Armory OSP Hellcat Adapter Plate Black