Vials 2 Ml Caps found in: Mass Spec Certified Vial Kits, E-C Vials w / Rubber Lined Caps, Amber, 2 ml, 2 mL Graduated PFA Micro Vials without Caps, E-C.. Seven different cap colors, blue, pink, green, yellow, red, white and natural are standard on the 2.0 mL sizes. sizes.