They work at Prestan but sometimes they don't blow themselves up for students or me. Especially after someone uses a mannequin mouth instead of "pocket mask mockup" (humidity in the hallway I guess). The oropharyngeal opening collapses, making lung filling impossible. I cut off the ribbed straws and put the pieces (2 inches) in the mannequin's mouth, which helps, but they will still break in the invisible area of the neck. I haven't found a bag that doesn't, but if someone should say prestan.
GRANDORF SINGLE GRAIN CAT ADULT SKIN & COAT CARE WHITE FISH & TURKEY
26 Review
π₯ Mylar Science Purchase: Your Ultimate Emergency Blankets
9 Review
High-Performance Arcturus Military Wool Blanket
12 Review
π₯ Stay Prepared in Extreme Conditions: EVERLIT Emergency Reusable Kit - Ultimate Thermal Survival Gear
10 Review