This refill pack contains a single, clear Comfort Size 2 mouthpiece that provides a slightly greater and6mm jaw adjustment. Size 2 is recommended for those with an underbite or a normal bite with heavy snoring. If you're new to , consider starting with the 2-Size Starter Pack to determine which size resolves your snoring. Once you've identified your ideal size, order either Size 1 or Size 2 separately. 's mouthpiece is soft, low-profile, and flexible, providing a lightweight, comfortable feel. It's less bulky and intrusive than similar products with a hard plastic shell. ¡¯s living hinge technology with an open front design lets you open and close your mouth naturally and even allows you to talk or take a sip of water. Minor side effects, such as drooling or jaw discomfort, are normal and tend to fade with consistent use. (See tips on adjustment in the content below. ) For proper hygiene and optimal performance, replace your mouthpiece every 4-6 months. Allows you to open and close your mouth freely Unobtrusive with enhanced wearing comfort No boiling or molding needed Enables natural breathing Living Hinge Technology Soft, Thin and Lightweight Ready to Use Open Front Design Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.