Springfield Armory Echelon Variable Interface System Plate For Docter Footprint Black. Constructed of steel and finished with a corrosion-resistant nitride coating the Docter and ACRO adapter plates allow users to mount additional red dot optics to the Springfield Armory Echelon. Specifications for Springfield Armory Echelon Variable Interface System Plate For Acro Footprint: Manufacturer: Springfield Armory Fabric/Material: Steel Color: Black Gun Model: Springfield Armory Echelon Package Contents: Springfield Armory Echelon Variable Interface System Plate For Acro Footprint What firearm models does the manufacturer say Springfield Armory Echelon Variable Interface System Plate For Acro Footprint is compatible with? The manufacturer says that Springfield Armory Echelon Variable Interface System Plate For Acro Footprint is compatible with Springfield Armory EchelonSpringfield Armory EC5077-DOC-SET: Echelon Variable Interface System Plate For Docter Footprint Black