20 years on the market with 900,000 units sold in all model! No. 1 portable negative ion generator. A healthy lifestyle item popular with large numbers of users. Sold in over 20 countries worldwide. Also popular with medical professionals. Features 1.It’s compact! Weighs just 23 grams 2. Patented negative ion barrier protects your body. 3. Eliminates 99.9% of PM2.5 4. Negative ion output of 690,000/cm³ 5. Class 5 ion emission certification by JAIRA *Japan Association of Ion Research and Application (JAIRA). JAIRA is a nonprofit organization established in 2001 to perform accurate measurements that will help advance the industry of ion-generating products. Specifications Colors : Khaki Size : 60mm(h) x27mm(w)x16(d) Weight: 23g Body material : ABS resin Power : Lithium battery, AC/DC adapter Operating environment : 0℃ to 40℃, Humidity 30-70% Value of negative ion emission : Approx. 750,000/cm3 Warranty : 6 month from purchase. Included power adapter and nickel free strap in package.