Twentieth Supplemental Indenture, dated as of April 1, 2019, by and among MasTec Inc., MasTec, Inc.s subsidiaries party thereto, as guarantors, and U.S. Bank National Association, as trustee

TWENTIETH SUPPLEMENTAL INDENTURE (this “Twentieth Supplemental Indenture”), dated as of April 1, 2019, among KINGSLEY CONSTRUCTORS, INC., a Texas corporation (the “New Guarantor”), MASTEC, INC., a Florida corporation (the “Company”), and U.S. BANK NATIONAL ASSOCIATION, as trustee under the Indenture referred to below (the “Trustee”).

WHEREAS the Company has heretofore executed and delivered to the Trustee an indenture (as amended, supplemented or otherwise modified, the “Indenture”) dated as of June 5, 2009, providing for (i) the issuance by the Company from time to time of its senior debt securities evidencing its unsecured and unsubordinated indebtedness, in an unlimited aggregate principal amount, in one or more series and (ii) the guaranty of such securities by the guarantors party thereto;

WHEREAS the Company has heretofore supplemented the Indenture by, among other things, executing and delivering to the Trustee (i) the Fifth Supplemental Indenture, dated as of March 18, 2013 (the “Fifth Supplemental Indenture”), by and among the Company, the guarantors party thereto and the Trustee, relating to the Company’s 4.875% Senior Notes due 2023 (the “Notes”), (ii) the Sixth Supplemental Indenture, dated as of September 30, 2013, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (iii) the Seventh Supplemental Indenture, dated as of November 11, 2013, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (iv) the Tenth Supplemental Indenture, dated as of July 10, 2014, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (v) the Eleventh Supplemental Indenture, dated as of August 8, 2014, by and among the Company, the guarantors party thereto and the Trustee, relating to the joinder of certain subsidiaries as subsidiary guarantors, (vi) the Twelfth Supplemental Indenture, dated as of December 8, 2014, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (vii) the Thirteenth Supplemental Indenture, dated as of April 10, 2015, relating to certain amendments to the Indenture, (viii) the Fourteenth Supplemental Indenture, dated as of January 7, 2016, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (ix) the Fifteenth Supplemental Indenture, dated as of September 1, 2016, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (x) the Sixteenth Supplemental Indenture, dated as of March 7, 2017, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (xi) the Seventeenth Supplemental Indenture, dated as of July 28, 2017, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, (xii) the Eighteenth Supplemental Indenture, dated as of November 1, 2017, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors, and (xiii) the Nineteenth Supplemental Indenture, dated as of June 29, 2018, relating to the joinder of certain subsidiaries of the Company as subsidiary guarantors;

WHEREAS Section 4.15 of the Fifth Supplemental Indenture provides that under certain circumstances, the Company is required to cause the New Guarantor to execute and deliver to the Trustee a supplemental indenture pursuant to which the New Guarantor shall unconditionally guarantee all the Company’s obligations under the Notes and the Indenture on the terms and conditions set forth herein (the “Guarantee”); and

WHEREAS pursuant to Section 901 of the Indenture and Section 9.01 of the Fifth Supplemental Indenture, the Trustee, the Company and the New Guarantor are each authorized to execute and deliver this Supplemental Indenture.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the New Guarantor, the Company and the Trustee mutually covenant and agree for the equal and ratable benefit of the holders of the Notes as follows:

or agreement of any obligor in this Indenture, or in any of the Notes or Guarantees or because of the creation of any Indebtedness represented thereby, shall be had against any incorporator, stockholder, officer, director, employee or controlling person of the Company or of any Subsidiary or of any successor Person thereof. Each Holder, by accepting the Notes, waives and releases all such liability. The waiver and release are part of the consideration for the issuance of the Notes. Such waiver may not be effective to waive liabilities under the federal securities laws.