- Brand: ZagoSystem of Measurement: Unified (inch)Mil-Spec: NoHead Type: HexO-Ring Material: Fluorosilicone RubberThread Size: 4-40Length: 3/4"Material: Stainless SteelFinish: PlainLocking Element: NoneDrive Type: HexHead Diameter: 3/16"Head Height: 1/16"Thread Fit: Class 2AThread Type: UNC