The standard size for a tongue bar is 1.6mm thick (14g) and 16mm long. This fits the vast majority of people, although some may feel more comfortable with a longer or shorter bar, for many types of tongue bars all you need to do is swap the barbel for a longer one, however you need to check if the barbell you are purchacing has fixed or threaded ends.
Steel and titanium are the most popular metals for tongue bars. Sometimes steel will be coted with coloured titanium, this is called titanium anodised. Tongue bars can also be made of yellow or white gold, or be gold plated.
Flexible tongue bars are becoming more and more popular. These are bars that bend and flex under pressure. Unlike a metal bar, a flexible bar with bend if it is bashed against a tooth. This significantly reduces the risk of tooth damage when wearing a tongue bar.
Flexible tongue bars come in all sorts of colours including including black red, white, green, orange, blue, pink and purple. They are also available in clear and make very good retainers for those times when you need to keep your piercing less visible.
Flexible tongue bars are often UV reactive or Glow in the Dark. Sometimes they have glitter or other novelty designs on the balls.
Flexible Body jewellery can be made out of various materials. PTFE is common as is Bioflex, a bio-compatible and hypo-allergenic plastic brought to the body piercing market in 2001.
Another benefit of PTFE and Bioflex is that it can be cut to the correct length using ordinary scissors and a new thread can be added using a standard metal threaded ball (or special threading tools are available). This means that the customer can self adjust the bar to their perfect length.