1. High quality material: 316l surgical steel (stainless steel). Resistant and durable with good skin compatibility, lightness and color fastness, also absolutely harmless for allergy sufferers.^ 2. Package content: 18 pairs incl. 36 pieces (18pcs expansion rods 1.6 / 2 / 2.5 / 3/4/5/6/8 / 10mm + 18pcs tunnel plug1.6 / 2 / 2.5 / 3/4/5/6 / 8 / 10mm)^ 3.Each expansion pin has double rubber-like O-rings. You can choose the 3rd size to be pierced with the correct gauge piericng according to your own. As a stretching beginner or more experienced in gentle stretching, this stretching set is guaranteed to be the right choice for you.^ 4.Good gift for Christmas Birthday Valentine's Day Thanksgiving Classic punk^ 5. Note: If you bathe, swim, have lunch or sleep at night, then you should take off the piercing. When using it for the first time, the best way is to consult a professional or experienced user. Applicable to people aged 15-50 years. People who are allergic to skin or have skin conditions must be used with caution or even prohibit its use.