The 500ml capacity is important for nasal irrigation. 500ml is strongly recommended. I myself use 500ml. As a user, with 300ml, I still feel like it's not completely flushed out, leaving an insufficient feeling, but with 500ml, I feel that the cleaning reaches every corner of the nasal cavity. Don't lose to Corona! Virus countermeasures House dust Yellow sand PM2.5 Pollen countermeasures! Effective for rhinitis and sinusitis! Care for dust, etc., and cleaning of the nasal cavity! Also effective in preventing colds! In addition, nasal irrigation is attracting attention from various organizations for its various health benefits. Nasal irrigation is possible with a cup, but using this device makes it really easy to do nasal irrigation without any difficulty. It's definitely easier(^^) How to use Mix about 4.5g of salt with 500ml of lukewarm water or water to make saline solution. Unlike ordinary water, by using a constant saline solution close to body fluids, you will not feel a stinging pain in your nose. I myself use it every morning. I recommend using it daily for your health. Body care Health Relaxation Rhinitis Hay fever House dust Dust Allergies Yoga corona Yellow sand Sinusitis Omicron 8