Anodised rainbow circular barbell also know as a horseshoe.
 
Available in 1.2mm by  8mm internal diameter with 3mm balls.
The balls can be unscrewed at both ends to allow for fitting or to change the balls.

Circular Barbell jewellery is very versatile and can be worn in many piercings such as septum piercing, ears, lips, daith, and tragus.