SURE-LINK™ PTFE Expansion Joints are available in multiple configurations commonly referred to as: Couplings: Two convolution connectors designed for minimum movements. Pressure: to 178 psig (12 bar) Full Vacuum: to +350°F (+180°C) Expansion Joints: Three convolution connectors designed for easy movement and ease of system installation. Pressure to 132 psig (9 bar) Full Vacuum to +180°F Bellows: Four or five convolution connectors designed for maximum movements and vibration eliminations. Pressure to 87 psig (6 bar) Vacuum to 17.7 In. Hg (0.6 bar) at 32°F (0°C) to No Vacuum at 212°F (100°C) Pressure and Vacuum Rating Garlock PTFE expansion joints and couplings have pressure ratings high enough to handle most applications. As the pipe size gets larger, Garlock increases the bellows thickness and the strength of the reinforcing rings to compensate for the change in internal forces. This permits the same high pressure.