... . Flush MountProcess Connector Gasket (11/2-in.)TFEProcess Connection O-rings (1-in.)Standard: Viton®. Optional: Buna-N or Ethylene propyleneNon-wetted ... Mutual (FM) ApprovalsE5 Explosion-Proof for Class I, Division 1, Groups B, C, and D.Dust-Ignition-Proof for Class II, Division ... safe for use in Class I, Division 1, Groups A, B,C, D; Class II, Division 1, Groups E, F, and G; and ...