| Feature | YAPOO YMD109 | Restrictive Mask (Steel) | Latex Gas Mask (Rubber) | | :--- | :--- | :--- | :--- | | | 3D Resin (Hard) | Stainless Steel | Latex/Rubber | | Weight | Very Light | Heavy | Medium | | Breathability | 10/10 | 4/10 (small holes) | 2/10 (Filters) | | Muffling | None | Moderate | Severe | | Cost | $$ | $$$$ | $$ | | Aesthetic | Cyberpunk | Medieval/Gothic | Military |
(or the dedicated 2.4G button) until the 2.4G indicator flashes to pair. Keyboard Layout & Special Keys The 109-key layout is modeled after the Japanese JIS standard , which includes extra keys for language switching. Alphanumeric Toggle : On many 109-key Japanese layouts, the key also functions as the Alphanumeric (英数, Space-Saving Design yapoo ymd109