#1 Home Improvement Retailer

Internet # 206517192

Model # MM300

Store SKU # 1003041814

Store SO SKU #1001572060

Manual Ranging Digital Multimeter

$34.97
Apply Now
Pay $9.97 after $25 OFF your total qualifying purchase upon opening a new card. 
Apply for a Home Depot Consumer Card
  • Manual-ranging multimeter tests batteries, diodes and continuity
  • Volt Tester measures up to 600 VAC/VDC voltage and 10A DC current
  • Electrical Tester for multi-purpose residential and industial use
  • View More Details

Free & Easy Returns In Store

Return this item within 90 days of purchase.

Read Return Policy

Ask about this product

Get an answer now with AI

Magic Apron Assistant is an AI virtual assistant. By proceeding, you consent to the recording and use of your information by The Home Depot (and authorized third parties). More information

Product Details

About This Product

Klein Tools MM300 Multimeter is a manual ranging multimeter that measures AC/DC voltage, DC current, and resistance. It can also test batteries, diodes, and continuity. Klein Tools' Test and Measurement product line was exclusively designed from the ground up by electricians for electricians. Years of field research, combined with extensive input from electricians across America, inspired the development of meters and electrical testers loaded with innovative, time-saving features.

Highlights

Product Information

Internet # 206517192

Model # MM300

Store SKU # 1003041814

Store SO SKU #1001572060

Specifications

Dimensions

Product Depth (in.)

1.78 in

Product Width (in.)

3.07 in

Details

Accuracy Measurement

Non-RMS

Category Rating

III

Features

Audible Alert, Data Logging, Interchangeable Leads

Functions Measured

Amperage, Continuity, Resistance, Voltage

Included

Batteries

Maximum AC Current (A)

0

Maximum AC Voltage

600

Maximum DC Voltage

600

Maximum Frequency (MHz)

0

Maximum Resistance (ohms)

2M

Number of Functions

16

Power Source

Battery Operated

Range

Manual Ranging

Returnable

90-Day

Warranty / Certifications

Certifications and Listings

CE Certified

Manufacturer Warranty

Please refer to the attached warranty document in the Product Overview section above under Info & Guides.

Questions & Answers

What dose OL stand for?
BySep 2, 2026
1 Answer | 
Answer This Question

On the Klein Tools Cat. No. MM300, Digital Multimeter, Manual-Ranging, 600V, “OL” indicates an open circuit when testing continuity. During diode testing, it indicates reverse bias or an open device.

By|Sep 4, 2026


    Operation of a Klein multimeter model mm100
    ByJun 16, 2026
    1 Answer | 
    Answer This Question

    The Klein Tools Cat. No. MM300, Digital Multimeter, Manual-Ranging, 600V includes an instruction manual with detailed operating instructions for measuring voltage, current, resistance, continuity, diodes, and batteries. Please refer to the instruction manual that was included with the meter for complete operating instructions. If you no longer have the manual or need additional assistance, please contact Klein Tools Customer Service at customerservice@kleintools.com and we will be happy to help.

    By|Jun 17, 2026


      What can be done if ohm test function does not work ?
      ByJan 5, 2025
      1 Answer | 
      Answer This Question

      Please contact Klein Tools Customer Service 1-800-553-4676 for assistance with your meter.

      By|Jan 6, 2025


        Does it come with calibration certification
        ByApr 1, 2024
        2 Answers | 
        Answer This Question

        For information on calibration certification please contact Klein Tools Customer Service 1-800-553-4676

        By|Apr 3, 2024

          For information on calibration certificates please contact Klein Tools Customer Service 1-800-553-4676

          By|Apr 3, 2024


            Does that voltage meter come with the batteries
            ByApr 16, 2023
            1 Answer | 
            Answer This Question

            Yes, batteries are included.

            By|Dec 27, 2023


              how long are the leads for MM325
              ByApr 7, 2023
              1 Answer | 
              Answer This Question

              39 in.

              By|Apr 10, 2023


                Will it measure millivolts on a gas furnace thermopile?
                ByMar 5, 2023
                1 Answer | 
                Answer This Question

                The Klein Tools MM300 Multimeter will measure DC millivolts.

                By|Mar 6, 2023


                  Since the meter is not auto-ranging, does the MM300 have over range or over voltage protection?
                  ByFeb 20, 2023
                  1 Answer | 
                  Answer This Question

                  The Klein Tools MM300 Multimeter has 2 replaceable fuses: 200mA/600V fast-blow fuse (Klein Cat. No. 69031) 10A/600V fast-blow fuse (Klein Cat. No. 69032)

                  By|Jun 6, 2024

                    (1)

                    Viewing 1-8 of 33

                    Customer Reviews

                    4.5 out of 5

                    • 4.5 out of 146 reviews
                    • 86% recommend this product
                    Filter by:
                    Showing 1-10 of 146 reviews
                    Get a better meter - good for short term use only
                    I buy Klein assuming longevity and reliability. This meter has failed on both accounts. After one year of good service, the meter is headed to the recycling. It currently it reads -213vac on the 600v scale, and -14.9v on the 200v scale, with no leads attached. Last time I used it I had funky readings too. Spurious results mean the tool cannot be trusted. Where the MM300 feels good and appears to be well build, please buy something better. This unit should not have the Klein name on it.
                    by
                      Have had it bout week, usage, forgot, alot. Still kicking. No complaints... Basic limited feature...
                      Have had it bout week, usage, forgot, alot. Still kicking. No complaints... Basic limited features, as said on back of package what was expected. Works well, just what I needed for the little I need for... Sturdy, WELL BUILT, ez read display, and use LOVE THE ORANGE (KLEIN) can't miss it ... Put it this way no instructions included so easy, unless u don't know what ur doing. ALWAYZ YOU TUBE Will also purchase the MM400. RECOMMENDED PURCHASE WELL WORTH FOR THE PRICE!!!
                      by
                      • Verified Purchase
                      • Recommended
                      3 found this review helpful
                      The Klein Tools MM300 is an affordable compact LED readout manual ranging multimeter
                      The Klein Tools MM300 is a great compact multimeter for use around the house or on a job site. The meter measures AC/DC voltage, DC current, continuity, and resistance. There also is a setting to test batteries, diodes, for continuity. The meter also has a built-in stand, and test lead holders integrated right into the meter housing. Requires 2 AA batteries which are included.
                      by
                      • Recommended
                      6 found this review helpful
                      Pretty paperweight
                      As the pictures will indicate, the LCD screen never lit up and there were no other signs of life from this device when turned on in spite of replacing the included batteries with new AAAs and following the instruction manual to the letter. It is a nice, durable looking instrument which just doesn't work. The instruction manual included directions to remove the back in order to replace the fuses. I did this and checked the fuses which were OK. Still - no joy! Serious disappointment.
                      by
                      11 found this review helpful
                      Very Impressive
                      This Klein MM300 Multimeter can measure AC/DC Voltage, DC Current, and Resistance. Can also test Batteries, Diodes and Continuity. Has a Hold Button and a large bright digital readout. Just make sure that you insert the test leads (Black & Red) fully into the meter. They have to click/lock into place without any gaps. This is outlined in the directions. I compared this unit with my neighbors $600 Multimeter and I found it to be 100% accurate. This meter is made out of high impact shock absorbent plastic with a built in stand and 2 clips on the back to hold your test leads in place. Each lead is about 39in. long and the tips can be removed to expose a longer test lead if needed. Uses 2 AAA batteries included and instruction manual included. Also a low battery indicator.
                      by
                      • Recommended
                      6 found this review helpful
                      Excellent multimeter for most people
                      This is a sturdy easy to read multimeter and can do most thing you’ll need it for. The stand and cable storage is nice too.
                      by
                        • Recommended
                        Easy to read and easy to operate...
                        Easy to read and easy to operate
                        by
                        • Verified Purchase
                        Easy to use.
                        Great meter to have around the house for checking light bulbs, batteries and AC outlets. affordable, and the best part it's one of the few meters still made in the USA.
                        by
                          • Recommended
                          So far, so good
                          I haven't used it much, but I have no complaints so far. I wish it came with a case.
                          by
                          • Verified Purchase
                          • Recommended
                          Worked for what I needed. Decent price....
                          Worked for what I needed. Decent price.
                          by
                          • Verified Purchase
                          Showing 1-10 of 146 reviews