2 dram (1/4 ounce, 7.5 ml) glass vials with polycone lid for extra leak protection. We use these for all of our oils and they're pretty good at not leaking as long as you don't store them upside down and jostle them a lot.
Roughly .67 x 2.36 in (17 mm x 60 mm)
Available in clear or amber glass.