Accuracy Solutions BipodeXt Picatinny Rail Flat Black FB-16S REV. They are coated to the U.S. MIL-A-8625 Type III Class 2 Anodize specification. The rails are U.S. MIL-STD-1913 compliant and attache to inserts that accept 10-32 Bolts. Specifications for Accuracy Solutions BipodeXt Picatinny Rail: Manufacturer: Accuracy Solutions Color: Black Finish: MIL-A-8625 type III class 2 anodizing Fabric/Material: 6061-T6 Aluminum Gun Rail: Picatinny Weight: 2.625 oz Condition: New Features of Accuracy Solutions Picatinny Rail 16 S. Flat Back Description 16-Slot Flat Back Rail General Specifications Material: 6061 T6 Aluminum Dimensions: OAL 6.70in Color: Flat Black Coating: U.S. MIL-A-8625 Type III Class 2 Anodize Attachment: 10-32 Bolt Rail: U.S. MIL-STD-1913 Hardware: 2 10-32 Bolts and nuts Weight: 2.10 oz Package Contents: Accuracy Solutions BipodeXt Picatinny Rail Accuracy Solutions FB-16S REV A: BipodeXt Picatinny Rail Flat Black