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Learn How to Combine the Perfect Test Tube and Cap Combination

All About Test Tubes, Caps and Racks

Sonic Supply offers an extensive line of Globe Scientific plastic multi-use test tubes, glass culture tubes and various forms of caps for every application. Every combination of tube and cap have different capabilities. The majority of our products are made from high grade plastic materials. The benefits of having plastic lab supplies is that they are less likely to break and are often less expensive than their glass counterparts. Plastic test tubes come in two different types of materials; those being polypropylene and polystyrene. Lets go over the key differences of each plastic compound.

Polypropylene (PP)
  • Rugged and unbreakable
  • Autoclavable and freezable
  • Translucent material
  • Excellent chemical resistance
  • Can spin at high rates in a centrifuge up to 3,000 RPM
  • Not a clear and see-through material
  • Temperature range -20 to +135 degrees Celsius
Polystyrene (PS)
  • Clear see through transparent material
  • Can withstand up to 1,500 RPM in a centrifuge
  • Easier to see substances in the tube
  • Only moderately resistant against chemicals
  • Not autoclavable
  • Temperature range -40 to + 90 degrees Celsius
When it comes to tubes, there are many different styles and sizes available. The major types of tubes Sonic Supply offers are glass culture tubes, plastic multi-use test tubes, transport tubes and centrifuge tube

Plastic Test Tubes

Sonic Supply offers plastic test tubes molded from either polystyrene or polypropylene. Sizes range from 11mm to 17mm with capacities ranging from 3mL to 19mL. For samples that are affected by light radiation, blue and amber-colored test tubes are also available.

False Bottom Tubes are ideal for use as a secondary tube for barcoding on automated analyzers.

Graduated test tubes allow for more accurate measurements. Graduation marks are listed in intervals of 1mL.

Flat-bottom test tubes are self-standing and come in 12mL Polypropylene or 2mL polystyrene.

Glass Culture Tubes

Glass culture tubes are also another option. These are best used when you have to heat or boil a substance. However, there are also some downfalls of buying glass like decreased durability and a higher risk of injury in the lab if the glass shatters. Our Globe test tubes are made from borosilicate glass instead of soda lime glass in order to reduce any changes in PH levels. These glass tubes are most often used in tissue culture and blood banks. All glass culture tubes sold from Sonic Supply come with heavy-duty packaging to prevent breakage during shipping. Choose from capacities ranging from 3mL to 15mL.

Transport Tubes

Transport tubes are excellent for safely storing and transporting specimens or biological materials. All tubes feature a color-coded screw cap, are shatter-proof and may be exposed to freezing temperatures. Choose from 5mL to 10mL and everything in between, in a polypropylene plastic material.

Centrifuge Tubes

Our line of centrifuge tubes ranges from simple general-purpose tubes to RNase/DNase-free products. Flared top tubes make for easy pouring of samples. General purpose tubes feature printed graduation marks and a writing area. Capacities range from 12mL to 50mL. All of our sterile centrifuge tubes are Rnase/Dnase and Pyrogen free. Choose from sterile or non-sterile varieties.

Micro-centrifuge tubes are available with or without attached caps. All tubes are made from a chemical-resistant polypropylene that can be autoclaved at 130°C. The tubes are manufactured from FDA-approved resins and are certified to be RNase-free, DNase-free, DNA free and Pyrogen free. These microcentrifuge tubes are also offered in resealable, tamper-evident self-standing bags.

Caps for Test Tubes

One would use test tube caps not only to close the tubes to prevent leaking but also to make it easier to identify your substances. Certain caps have different applications like our pierceable Santoprene stoppers which can be pierced with a syringe for easy sample taking. Let's take a look a variety of caps sonic supply has to offer. Find the right cap by matching the test diameter to the diameter of the cap or invest in universal caps that fit multiple-sized tubes.

Flange caps: These caps provide exceptional leak resistance in test tubes, centrifuge tubes, and round cuvettes. Flange caps feature flanges that press against the inside wall of tubes providing better leak resistance than their standard plug caps counterparts. Sizes range from 12, 13, and 16mm and are offered in a variety of colors.

Snap Caps: A great effective way to recap glass culture tubes or multi-use plastic test tubes. All snap caps are made from low-density polyethylene and remain completely sealed during centrifugation, agitation and refrigeration. The snap cap's two thumb tabs are designed for easy removal of the cap. Choose from a variety of colors in 13 and 16mm sizes.

Universal cap: These universal caps are made from polyethylene and are able to fit most 10mm, 12mm, 13mm, and 16m tubes. Choose from either snap caps or plug caps.

Dual Position snap cap: These caps are designed to provide aerobic or anaerobic storage of culture samples. When snapped into the tube, the cap provides a leak-resistant seal. Available in 12mm sizes.

Pierceable Santoprene Stoppers: Excellent caps for recapping vacuum blood tubes and test tubes. All caps can be pierced with a syringe for easy sampling. Available in 13mm sizes.

Test Tube Racks

Test Tube Grip Rack:

This specially designed test tube rack features rubber grips that hold test tubes in place when decanting liquid. Another key feature is that this rack can hold a variety of different size tubes up to 17mm in diameter.

Grip rack with tube ejectors:

These specially designed test tube racks feature rubber grips that hold test tubes in place when decanting liquid. These racks feature a unique tube ejector that allows the user to easily eject all tubes into a waste receptacle at once.

60 place test tube rack:

This rack design allows all samples to be incubated at the same temperature. They can be used in freezers without deforming or going brittle. They will not rot, rust of deform. Alphanumeric markings are molded into the racks to provide easy test tube identification.


Designed to hold both 15mL and 50mL centrifuge tubes in one rack. The rack ships flat and is simple to assemble. It holds twenty 50mL and thirty 15mL centrifuge tubes.

"Z" shaped rack:

These specially shaped "Z" racks are rust proof and will hold up to repeated use. The wide base provides stability and prevents tipping. When not in use, the racks stack neatly inside one another to conserve benchtop space.

72 Place Drying Rack:

The 72 (push-in) pegs can accommodate items with a 15mm+ neck bore. They are easily removable for cleaning or to accommodate odd-shaped items. Also included are 11 small pegs to accommodate small diameter items with a neck bore of 6mm+ (such as test tubes). This durable rack will not rust or stain.

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