https://photojournal.jpl.nasa.gov/catalog/PIA24306

This illustration depicts the exterior of a sample tube being carried aboard the Mars 2020 Perseverance rover.

About the size and shape of a standard lab test tube, the 43 sample tubes headed to Mars must be lightweight, hardy enough to survive the demands of the round trip, and so clean that future scientists will be confident that what they are analyzing is 100% Mars, without Earthly contaminants.

Exterior Ball Lock: Placed on opposite sides of the tube, the two ball locks help secure the sample tube as it progresses through the many stages of sample collection and storage. Serial Number: Helps with identification of the tubes and their contents. Titanium Nitride Coating: Gold in color, this extremely hard ceramic coating is used as a specialized surface treatment that resists contamination. Alumina Coating: The reflective coating provides thermal protection and acts as a sponge to prevent potential contaminants from getting inside the sample tube. Bare Titanium: The portion of tube near the open end contains no coating to eliminate the possibility that the coating could delaminate from this portion of the tube during the insertion of a hermetic seal. Bearing Race: An asymmetrical flange at the open end of the tube, it assists in the process of shearing (breaking) off samples at the completion of the coring portion of sample collection. JPL built and will manage operations of the Mars 2020 Perseverance rover for NASA.