Material: Metal. Thread Type: High/Low. Size: 5/16 in. Anchor Length: 18 in. Application: For 5/16-18. Number in Package: 5. Screw Length: 18 in. Anchor Width: 0.3125 in. Unit of Measurement: SAE. Head Style: Round. Pro grade. Installs "caulk-in" machine screw anchor.