The highest quality essential oils mixed with a jojoba carrier oil in a blue glass bottle (protects oil from light), with a handy-dandy roller-ball. Makes for very easy application.
I apply mine to temples, back of neck or bottoms of feet. The rolling motion against the skin is very soothing.
Peppermint is one of my favorite oils as it is very effective for headaches.
The reason I apply to the bottoms of the feet are: The pores on the bottom of the feet are large, the skin is less sensitive and the feet have many nerve endings and reflex points.