Caps for Split-Flange Connections - SF SERIES Size: 3/4" Series SF Caps and Covers are designed to protect four-bolt split-flange connections. Series SF Caps push on easily and fit securely with an internal bead providing a positive locking grip. Inasmuch as the SF Cap is made of natural, translucent polyethylene, the O-ring remains visible even after the closure is applied.Material: Low-Density PolyethyleneColor: Natural