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Table of Contents X UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ( Mark one ) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended March 31 , 2021 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Title of each class Common stock , no par value FORM 10 - K Colorado ( State or other jurisdiction of Incorporation or organization ) Commission File No : 0-11740 12100 West Sixth Avenue Lakewood , Colorado ( Address of principal executive offices ) MESA LABORATORIES , INC . ( Exact name of registrant as specified in its charter ) to Trading Symbol MLAB 84-0872291 ( I.R.S. Employer Identification number ) 80228 ( Zip Code ) Registrant's telephone number , including area code : ( 303 ) 987-8000 Securities registered under Section 12 ( b ) of the Act : Securities registered under Section 12 ( g ) of the Act : None Name of each exchange on which registered The Nasdaq Stock Market LLC