Until recently, scientists had no idea what the 5,500-year-old gold tubes found in a burial mound near Maikop were for. Now, it turns out that the items may have been drinking straws—the oldest-known ones ever discovered. Archaeologists made this conclusion after discovering traces of ancient beer in the residue lining the tubes’ inner walls, reports the Washington Post.

A2900: The rare, high-quality tube from the Genalex “Gold Monarch” series. The tubes are usually engraved with the words “Gold Monarch” and a red Genalex decal logo on the top of the tube. They feature wide black plates, and are known for their high, well-controlled noise specs and audio perfection. Any scarcer and they would be museum pieces!

Royal blue-top Monoject tubes (also called EDTA tubes) contain the anticoagulant EDTA. These tubes are used for blood trace element analysis. Immediately after collecting, invert the tube 6 to 8 times to ensure proper mixing with the anticoagulant.

Serum-separating tubes (also called SSTs, marbelled red and grey tubes or tiger-top tubes) are test tubes for clinical chemistry tests that require serum. The tubes are typically capped with stoppers that are gold, red with a gold ring on top or marbled red and grey. Trademarked versions include Covidien’s “Corvac” tubes and Roche’s “SST” tubes.

The RCA 12AT7 is a rare military type tube with wing shape black plates and a large capital letter “T” in a yellow triangle on the glass. They are a bit scarcer than the A2900, and have thick mica spacers. They also have an audio quality very close to the Genalex Gold Lion, and are a good choice for phono use.