Organizing cryogenic samples is easy with these brightly colored cryovial inserts that work with ourCryoForge brand of polypropylene cryovials. Colored cap inserts work with BOTH internal and external threadCryoForge cryovials. The cap surface is smooth and offers a small space for notation. One end of the cap contains a divot to be used if removal of the cryovial cap insert is needed. Sold in packs of 500 cryovial caps.