## 4 Discussion and Conclusions
In addition, participants responded that they felt more pressure on the earhole area when the size of the earhole was large, even with the same kernel-type product. The average length of the participants' ear canal was 0.73 cm, and the average width of their ear canal was 0.59 cm, while sample product three had the largest size of 0.9-1.2 cm, which caused the highest pressure on the ear canal. According to responses to the adequacy of the design factors, there were many responses that the size of the earhole contact area was appropriate for products between 0.6 and 0.7 cm in size, and the larger the size, the lower the ratio. Therefore, when designing kernel-typeproducts, it is necessary to reduce the feeling of pressure by considering the size of the ear tip part that contacts the ear canal area. The Kernel-type products, on the other hand, scored a high level of sense of fixation. Since kernel-type products are designed to reach the inside of the ear canal and are fixed to the ear canal, providing a strong sense of fixation. However, in the case of sample product three, the size of the ear tip (the part that contacts the ear canal) was designed to be larger than the size of the ear, so the ear tip could not properly be held to the inside of the ear canal. Thus, the sense of fixation was lowered even it was a kernel-type product. The touch-type products (the sample product one and two) caused less pain to the participants. In general, the wireless earphone is operated by touching the product or pressing a button, causing pain due to pressure applied to the area where the earphone is worn. In the case of the button-type products (sample products three and four), the pressing force is stronger than that required for the touch-type products, which can cause more pain. In the case of sample product three, the pain in the earhole area was the highest because the product was in contact with the inside of the earhole, causing more pain in the earhole area while pressing the button. In the case of sample product four, the pain in the concha area was also high while operating because the button-type method was used to cover the concha area. Moreover, the pain in the area was caused by contacting the product while pressing the button. The comfort of the ear canals was higher in the open-type products than the kernel-type products. In terms of the earhole, the open-type ones had a higher comfort rating than the kernel-type ones. These results indicate that the open-type ones were designed to be worn without contacting the inside of the earhole, providing a greater level of comfort in the earhole compared to the kernel-type products. Regarding the comfort in the concha area, however, there was a difference in the results between both open-type products. The comfort of the concha area was the highest in sample product two (concha area size: 1.7 cm \(\times\) 1.7 cm) with the smallest main body of earphone (concha contact area), and it was lowest in sample product four (concha area size: 2.2 cm \(\times\) 2 cm). The average width of the participants' concha area was 1.8 cm, indicating that the main operation part size (head size) of sample product four is designed to be larger than the ear size. According to the evaluation on the appropriateness of earphone sizes, the larger the size of earphones, the less appropriate they are. This shows that although both products are the same as open-type, the level of comfort in the ears varies depending on the size of the product. The earphones used in the experiment weighed between 4-7 g (g), and most participants responded that the lower the weight, the more appropriate. For example, they replied that the lightest weight of 4 g was the most appropriate, but the heaviest weight of 7 g was the least appropriate. Since the ear area is more sensitive than other body parts [21], the difference between weights can be accurately recognized [8].