<ul><li>Plastic film containing a one-way valve.</li><li>Film acts as a barrier to help prevent infection.</li><li>One-way valve allows expired air ventilation.</li></ul> Reliance Rebreath Mouth To Mouth Shield With One-Way Valve (RL850) 850 Reliance Rebreath Mouth To Mouth Shield With One-Way Valve A transparent plastic film containing a one way valve allows expired air ventilation, for a safer and more effective method of resuscitation. The film acts as a barrier to reduce the risk of infection, possible from direct mouth-to-mouth resuscitation.