These tunnel are made of brass. You can hang them easily in your ear.
From size 20 mm you can hang them in your ear until 26 mm. Between 26 mm and 30 mm you use them in 26 mm. Between 30 mm and 36 mm you use them in 30 mm. Between 36 mm and 40 mm you use them in 36 mm. The one in 40 mm you can use for every size above.
The Raja tunnel are 100% handmade. This can lead to minor imperfections. All handcrafted jewelry can therefore be slightly different because of the organic materials.