8 x 40 x 40 mm Magnetic Stir Bar N42H STIR40

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STIR40 Specifications

Magnetization Direction: The direction through which the magnet is magnetized. See our Magnetization Directions page for more details.
Axial (through thickness)
Size: Size is the physical dimensions of the product using the standard unit of measure inches.

0.315 x 1.575 x 1.575 Inch ( Diameter x Length x Thickness )
Metric Size: Metric size is the physical dimensions of the product in metric millimeters.

8 x 40 x 40 mm ( Diameter x Length x Thickness )
Grade:
Grade N

Min: -238°F (-150°C) Max: 176°F (80°C)

Hover over grades for temp info:

N

NM

NH

NSH

NUH

NEH

NAH
N42H
Max Operating Temp: Maximum operating temperature, also known as maximum service temperature, is the temperature at which the magnet may be exposed to continuously with no significant long-range instability or structural changes. Learn more in our Temperature and Neodymium Magnets article.
248°F (120°C)
Material: This lists the name of the material each product is composed of.
Neodymium (NdFeb)
BH Max: BH max is the Maximum Energy Product at the point on the B/H Curve that has the most strength, expressed in MGOe (MegaGaussOersteds). When describing the grade of a neodymium magnet, this number is commonly referred to as the "N" number, as in Grade N52 magnets. Learn more about Bh max in our glossary.

42 MGOe
Tolerances: Dimensional tolerance specifies the allowed leeway for variations in manufacturing.
±0.1 in (2.5mm)
Coating: Most neodymium magnets are plated or coated in order to protect the magnet material from corrosion. Check out our Custom Magnets for unplated magnets and other coatings not stocked for this size magnet. Learn more about all available platings and coating in our What Magnet Coating Should I Use? article.
Molded PTFE
Weight: This is the weight of a single magnet in ounces and grams. Variety packs (with mixed sizes) show the overall weight.

0.2363 oz (6.7 g)
Br Max: Br max is also called "Residual Flux Density" and is when the magnetic induction remaining in a saturated magnetic material after the magnetizing field has been removed. This is the point at which the hysteresis loop crosses the B axis at zero magnetizing force, and represents the maximum flux output from the given magnet material. By definition, this point occurs at zero air gap, and therefore cannot be seen in practical use of magnet materials. Learn more about Br max in our glossary.

13,200 Gauss
Color: The color of the coating or plating on the product.

White

Product Description

The stir40 magnetic stir bar measures 0.315" (8 mm) in diameter and 1.575" (40 mm) in length and contains a powerful neodymium magnet inside a molded PTFE (teflon) coating. The smooth PTFE exterior provides excellent chemical resistance, helps protect the internal magnet from liquids and corrosive materials, and creates a low-friction surface for smooth rotation inside laboratory containers. Made with high-temperature N42H grade neodymium magnet material, the stir40 provides strong magnetic performance and can handle maximum operating temperatures up to 248°F (120°C).

The stir40 is a powerful N42H neodymium magnetic stir bar designed for mixing and stirring liquids when used with a compatible magnetic stirrer or stir plate. Its cylindrical shape and molded PTFE coating allow it to rotate smoothly inside laboratory containers while providing excellent chemical resistance and protecting the internal magnet from direct contact with liquids. Its strong magnetic performance and high-temperature construction make it a versatile choice for laboratories, researchers, scientists, educators, manufacturers, and hobbyists mixing solutions, chemicals, reagents, and other liquids. The stir40 provides efficient, hands-free agitation without requiring a mechanical stirring shaft to enter the container, making it useful for laboratory experiments, sample preparation, chemical processing, research, education, and other controlled mixing applications.

Common Applications

Beakers & Flasks - Mixing liquids in laboratory beakers and flasks.
Chemical Solutions - Preparing chemical solutions and reagent mixtures.
Dissolving Solids - Dissolving solids into liquids.
Scientific Experiments - Mixing samples during scientific experiments.
Non-Contact Mixing - Blending laboratory solutions without mechanical shaft mixing.
Uniform Mixtures - Maintaining uniform mixtures during testing and analysis.
Small-Batch Mixing - Mixing small batches of liquids in research laboratories.
Buffers & Formulations - Preparing buffers, solutions, and other laboratory formulations.
Heated Solutions - Stirring liquids during heating and temperature-controlled experiments.
Educational Laboratories - Mixing samples in educational and classroom laboratories.
Science & Research - Supporting chemistry, biology, and materials science experiments.
Testing & Product Development - Mixing liquids in research, testing, and product development applications.

Product Features

Magnetically Driven Mixing - Rotates inside a container when coupled with the rotating magnetic field of a compatible magnetic stirrer.
Compact Size - Provides strong magnetic performance in small, space-limited designs.
Smooth Outer Surface - Designed to rotate freely while minimizing interference with the vessel during stirring.
Chemically Resistant Coating - Protective exterior isolates the internal magnet from direct contact with many liquids and chemicals.
Reusable Design - Can be cleaned and reused for repeated mixing and laboratory applications.
Simple Operation - Requires no electrical connections or mechanical attachments to the stir bar itself.
Easy to Add and Remove - Can be placed directly into the vessel and removed after mixing or processing.
Permanent Magnet - Remains magnetized without requiring electricity, batteries, or an external power source.
Rare Earth Neodymium Magnet - The strongest type of permanent magnet available, providing exceptional strength for its size.