Ultra-Purewhip (50 pack). It’s the best-selling charger on the Internet for lots of reasons: 1. The formula is pure and professional. 2. Every one is made in Europe to high standards. Expires in 2025 You get the precise amount of gas you’re paying for. And these are heavy, leakless steel cases (not cheap, leaky aluminum). This is N2O (nitrous oxide) for whipping up cream, desserts, sauces and fancy cocktails.