Plugs and caps of various material compositions, sizes, colors, and closure types to fit a wide range of tube types; may be sterile, non-sterile, and/or autoclavable; may possess leak-preventing features including O-rings and cap liners.
Colored screw cap with o-ring fits empty 2 mL microfuge tubes. Green Caps for Lysing Matrix Tubes are used in conjunction for isolation of total RNA from plants and animals.