Teflon (PTFE, polytetrafluoroethylene) - Teflon is an inert wear-resistant, slippery and flexible plastic, and has been used extensively as a component of permanent and temporary surgical implants.
Benefits of PTFE:
1) Can be Sterilized with Autoclave
2) Totally Flexible - It will bend with your body tissues unlike all metal Jewelry.
3) Hypo-allergenic - Being one of the least allergic materials, P.T.F.E. is used in the medical industry to make Heart Valves and other surgical implants. Should there be a problem of allergic reaction or rejection to conventional metal jewelry, it is likely that PTFE Body Jewelry is now a practical choice for that person under any circumstances.
4) Fully Adjustable- A razorblade is all that is needed to adjust the bar to the exact size of your piercing!
5) Self Threading - PTFE bars will fit all threaded accessories that you may already own! Simply screw-on your accessory (balls, spikes, etc...) on to a PTFE bar. It will create a thread on the bar and will hold strongly.
OR
NYLON POLYMIDE MONOFILAMENT - Monofilament is used in medical applications, in wig making and most commonly known, fishing line. Monofilament is a single strand (hence... mono) of nylon. There is nothing to fragment or splinter. The type of monofilament we use is called monofilament nylon polyamide. It is strong flexible and non-biodegradable (will not break down even with prolonged wear in the human body). This is the same material used in non-absorbable suture material. Monofilament nylon polymide is listed with the FDA as 'non-absorbable suture materials' under nylon - listing no - A 100568.