Features: They are different, the one in blue is soft, it's for the first stage, while the one in transparent is hard, it's for the second stage. Made of EVA material, it dosen't have a plastic smell or taste to it, safe to wear. Designed for actively retrain the mode of the tongue and the peri-oral muscles of the mouth. Helps correct breathing habits and align the anterior dentition. With a mini denture case, convenient for travel and daily use. Specifications: Type: Dental Care Color: Transparent; Blue (Optional) Material: EVA Model: Hard, Soft (Optional) Item Size: Approx. 6.5 * 4.5cm / 2.56 * 1.77in Package Weight: Approx. 32g / 1.13oz Package Size: Approx. 7.7 * 6 * 2.4cm / 3.03 * 2.36 * 0.94in Package List: 1 * Tooth Orthodontic Appliance 1 * Denture Case