Hermetically sealed is in applications for impenetrable, barred, air and watertight, etc. The heart of a RF hermetic connector is about glass bead. Huang Liang Technologies provides a variety series of SMA, SMP, N, TNC glass bead for your selection. Glass is a better material than plastic for the insulator due to its physical characteristics such as high temperature resistance, stress- resistance, and corrosion-resistance and so on.