Practi-VALVE® for CPR Training by WNL Products is a set of practice valves with a filter for use in CPR training masks. The material used in the filters is the same material used in FDA-approved surgical masks. This material has a bacterial filtration efficiency (BFE) and a viral filtration efficiency (VFE) of 99.9%. Practi-Valves are single use only. Dispose of mouthpiece after use. Available in packs of 10 or 55 valves. Select the quantity desired by using the dropdown window above.