A durometer is an instrument for testing the hardness of rubber and various plastics. ASTM D2240 Standard Test Method for Rubber Property, Durometer Hardness. This test method covers twelve types of rubber hardness measurement devices known as durometers.

PTC® Instruments manufactures and calibrates durometers to ISO 17025. We offer calibration, repair and certification services. These durometers are available to ASTM D2240, ASTM F1957, JIS K-6301, JIS K-6253, DIN-53505, ISO-7619 and ISO-868 standards including many custom configurations. Our sales department will help you determine the correct durometer for your application. We offer material testing to determine the correct durometer type and style for your application at no charge.

Download Durometer Types & Specifications PDF

PTC® Durometer Styles

306L Durometer Classic
The Classic Style Durometers can be used either with a test stand, hand-held or with the constant load weight. Please refer to the stand selection guide for appropriate instruments.

ASTM... Type A | Type B | Type C | Type D | Type OOO

Durometer Ergo Style
The Ergo Style Durometers feature a removable knob for small confined areas while landing on a solid 1" x 1 " base.

The PTC® Ergo Style Durometers come complete with carrying case, test block and a magnetic max hand that holds the peak reading until reset.

ASTM... Type A | Type B | Type C | Type D | Type E | Type O | Type OO | Type DO | Type AO

Analog Durometer e2000
The design of the e2000™Analog is the ultimate in hand held hardness measurements. Easier handling and more repeatable readings are the result of PTC®'s Ergonomic Research. The 1.25" diameter base (3.2cm) is the most practical size for maximum repeatability and increased stability. All PTC® durometers come complete with test block, carrying case and max hand.

ASTM Type... Type A | Type B | Type C | Type D | Type E | Type O | Type DO

Durometer Pencil Style
The Pencil Style durometer's 1/2" diameter base (1.3cm) is the smallest base permitted by ASTM D2240 specifications. This allows it to be used in confined or hard to reach areas other durometers cannot test. A standard max hand holds the peak reading until reset. The dial has a red zone to indicate unreliable readings.

ASTM... Type A | Type B | Type C | Type D | Type O | Type OO | Type DO | Type Asker C

Digital Durometer e2000
PTC®'s e2000 Digital is the ultimate digital durometer for accurate hand held hardness measurements of the indentation hardness of rubber, elastomers, and other rubber-like substances.

ASTM Type... Type A | Type B | Type C | Type D | Type E | Type O | Type OO | Type DO

All PTC® digital durometers come complete with test block , carrying case and NIST traceable certificate from PTC Metrology™. US Patent D436,874

Digital Durometers Pencil Style
The Digital Pencil Style with a 1/2" diameter base (1.3cm) and overall length will allow the durometer to be used in confined or hard to reach areas with 0.1 reading resolution. A knurled surface gives a more secure grip when making hand held readings.

All Digital Durometers come complete with Electronic Max Hold feature, Test Block, Carrying Case and a NIST traceable certification. PTC Metrology™ is accredited by A2LA to ISO/IEC17025 and ANSI Z-540.

ASTM... Type A | Type B | Type C | Type D | Type O | Type DO | Type Asker C

Durometer Type (Scale)

Typical Examples of Materials Tested

Durometer Hardness

Type A

Soft vulcanized rubber, natural

rubber, nitriles, thermoplastic, elastomers, flexible polyacrylics, thermosets, wax, felt, and leathers..

20-90 A

Type B

Moderately hard rubber, thermoplastic elastomers, paper products, and fibrous materials

Above 90 A

Below 20 D

Type C

Medium-hard rubber, thermoplastic elastomers, medium hard plastics, and thermoplastics.

Above 90 B

Below 20 D

Type D

Hard rubber, thermoplastic, elastomers, harder plastics, and rigid thermoplastics

Above 90 A

Type DO

Moderately hard rubber, thermoplastic elastomers, and very dense textile windings.

Above 90 C

Below 20 D

Type M

Designed specifically for measuring small cross section O-rings and thin pieces of rubber (not less than 1.25mm thick).



Type O

Soft rubber, thermoplastic elastomers, very soft plastics, thermoplastics, and medium-density textile windings.

Below 20 DO

Type OO

Extremely soft rubber, thermoplastic elastomers, sponge, extremely soft plastics and thermoplastics, foams, low- density textile windings, and human & animal tissue.

Below 20 O

Type OOO

Very soft materials, (e.g.) open cell foam.


Type OOO-S

Very soft materials, (e.g.) open and closed cell foams, viscoelastic polymers, sponge rubber.


Type CF

Composite foam materials, such as amusement ride safety ASTM F1957 cushions, vehicle seats, dashboards, headrests, armrests, and door panels.

ASTM F1957

PTC® manufactures durometers to test the material hardness of...

See below for some of PTC®'s Custom Durometers

Composite Foam Durometer 414CF
PTC®'s 414CF ASTM F1957 Composite Foam Durometer

The PTC® Model 414 Type CF Durometers are manufactured and designed to measure the indentation hardness of all generations of foam products: Freon Blown types, Water Blown types and new Composite Foams. The instrument features a low glare aluminum serialized dial with bold, easy to read numbers. The durometer has a maximum reading hand for indicating peak readings test block and carrying case are also included. This product meets or exceeds the current ASTM F1957 standard test method for composite foam hardness, which was created at the task group level within ASTM Committee F24 on amusement rides and devices.

Drywall Durometer
PTC®'s 414USG Drywall Durometer

PTC®'s Model 414USG Durometer measures hardness of drywall sheets during processing. Drywall can be checked for proper curing before the cutting stage. The instrument features a low glare aluminum serialized dial with bold, easy to read numbers. The durometer has a Max Hold hand, which retains the peak reading. A test block and carrying case are included with the instrument.

Foam & Sponge Rubber Durometer
PTC®'s 302SL Foam & Sponge Rubber Durometer

The Model 302SL is a hand-held foam and sponge rubber hardness tester made exclusively by PTC® Instruments. The instrument has the capability to economically test the same type of material checked with an ILD tester. There is no direct conversion from the 302SL scale to ILD readings, however, the 302SL can be used for comparative testing.

Crab & Lobster Shell Durometer
PTC®'s Crab & Lobster Shell Durometers

Developed with the Alaska Dept. of Fish and Game and the Canadian Department of Fisheries and Oceans
  • Used by Fish and Game to Enforce Fishing Regulations.
  • Used by Marine Biologists for Crab Fisheries research.
  • Accurately measures shell hardness
  • Magnetic Max Hand
  • NIST Traceable Certification Available

Renfro Durometer
PTC®'s Renfro Durometer

Developed for National Association of Hoisery Manufacturers (NAHM)

Racing Tire Durometer

PTC®'s Racing Tire Durometer

This durometer specifically tailored to measuring racing tire hardness. The Model 306RL durometer is the first choice for use by tire manufacturers, technical inspectors, race teams, and engineers fast and accurate tire hardness.