An ear piercing instrument (commonly referred to as a piercing gun or an ear piercing gun) is a device designed to pierce earlobes by driving a pointed starter earring through the lobe. Piercing guns may be reusable or disposable. Piercing guns are typically used in mall jewelry shops. Piercing guns have been widely criticized as dangerous among professional body piercers. The use of older designs of piercing gun can possibly carry an increased risk of disease transmission, as compared to methods used by professional piercers. However, more modern designs of reusable piercing gun have addressed this problem by the use of self-contained disposable cartridges. With these new designs, all parts of the gun that could come into contact with the customer's body are made of medical-grade plastic, which is sterilised at the time of manufacture and stored in sealed packaging that is only opened immediately before use in exactly the same way as the needles used by body piercing establishments. This automatically removes the problem of possible disease transmission found in the earlier types of device. There are still the issues of blunt force trauma to the skin and underlying tissue. Standard ear piercing studs are too short for some earlobes and most cartilage. Diminished air and blood circulation in tissue compressed by a piercing gun can lead to prolonged healing, minor complications and scarring. However, this problem has also been addressed in more recent gun-based systems, which use longer and thinner posts on the earrings, which also have much sharper points. These newer designs reduce the trauma to the skin and tissue, but cannot compare to hollow needles used professionally. Also, while most older ear piercing studs were not made of materials certified by the FDA, ISO, or ASTM as safe for long term implant in the human body, which could lead to materials from underlying alloys leaching into human tissue through corrosion, scratches and surface defects, causing cytotoxicity and allergic reaction, more recent designs offer much safer options such as titanium. Design and use Traditional model The most common design uses a spring that stores potential energy when part of the ear piercing instrument is pulled back. Pre-sterilized starter studs and matching friction backs are typically provided in pairs by the piercing gun manufacturer in sealed containers. A starter stud has a point that is designed to penetrate the earlobe when the mechanism is released. Ear piercing instruments