First Supplemental Indenture



 Exhibit 10.3 
 FIRST SUPPLEMENTAL INDENTURE 
 FIRST SUPPLEMENTAL INDENTURE (this “Supplemental
Indenture”), dated as of December 30, 2005, among, MDAS, Inc., a Delaware corporation (“MDAS”), Murray’s Discount Auto Stores, Inc., a Michigan corporation (“Murray’s Stores,” together with MDAS, the “New
Guarantors” and each a “New Guarantor”), CSK AUTO, INC., an Arizona corporation (the “Company”), CSK AUTO CORPORATION, a Delaware corporation and the parent of the Company (the “Issuer”), and THE BANK OF NEW YORK
TRUST COMPANY, N.A., a national banking association, as trustee under the indenture referred to below (the “Trustee”). 
 WITNESSETH: 
 WHEREAS the Company, the Issuer and the existing
Subsidiary Guarantors have heretofore executed and delivered to the Trustee an Indenture (as amended, supplemented or otherwise modified, the “Indenture”) dated as of December 19, 2005, providing for the issuance of the Company’s
4 5/8% Senior Exchangeable Notes due 2025 (the “Notes”), initially in the aggregate principal amount of $85,000,000 (or
up to $100,000,000 if the Initial Purchasers exercise their over-allotment option set forth in the Purchase Agreement in full), and Additional Notes as provided in the Indenture; 
 WHEREAS Section 4.10 of the Indenture provides that under certain circumstances the Company is required to cause each New Guarantor to execute and
deliver to the Trustee a supplemental indenture pursuant to which such New Guarantor shall unconditionally guarantee all the Company’s obligations under the Notes and the Indenture pursuant to a Guarantee on the terms and conditions set forth
herein and in the Indenture; and 
 WHEREAS pursuant to Section 10.01 of the Indenture, the Trustee, the Company, the Issuer and the
existing Subsidiary Guarantors are 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, each New Guarantor, the Company, the Issuer and the Trustee mutually covenant and agree for the equal and ratable benefit of the holders of the
Notes as follows: 
 1. Defined Terms. As used in this Supplemental Indenture, terms defined in the Indenture or in the preamble or
recital hereto are used herein as therein defined. The words “herein,” “hereof” and “hereby” and other words of similar import used in this Supplemental Indenture refer to this Supplemental Indenture as a whole and not
to any particular section hereof. 
 2. Agreement to Guarantee. Each New Guarantor hereby agrees, jointly and severally with the
Issuer and all existing Subsidiary Guarantors, to unconditionally guarantee the Company’s obligations under the Notes and the Indenture on the terms and subject to the conditions set forth in Article 15 of the Indenture and to be bound by all
other applicable provisions of the Indenture and the Notes and to perform all of the obligations and agreements of a Subsidiary Guarantor under the Indenture. 







 3. Notices. All notices or other communications to each New Guarantor shall be given as provided
in Section 16.03 of the Indenture. 
 4. Ratification of Indenture; Supplemental Indentures Part of Indenture. Except as
expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect. This Supplemental Indenture shall form a part of the Indenture for all
purposes, and every holder of Notes heretofore or hereafter authenticated and delivered shall be bound hereby. 
 5. Governing Law.
THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK 
 6. Trustee
Makes No Representation. The Trustee makes no representation as to the validity or sufficiency of this Supplemental Indenture. 
 7.
Execution in Counterparts. This Supplemental Indenture may be executed in any number of counterparts, each of which shall be an original, but such counterparts shall together constitute but one and the same instrument. 
 8. Effect of Headings. The titles and headings of the Sections of this Supplemental Indenture have been inserted for convenience of reference
only, and are not to be considered a part hereof, and shall in no way modify or restrict any of the terms or provisions hereof. 
  

 2 








 IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of
the date first above written. 
  

			
	MDAS, INC.
		
	By:	 	 /s/ RANDI VAL MORRISON

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	MURRAY’S DISCOUNT AUTO STORES, INC.
		
	By:	 	 /s/ RANDI VAL MORRISON

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	CSK AUTO, INC.
		
	By:	 	 /s/ RANDI VAL MORRISON

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	CSK AUTO CORPORATION
		
	By:	 	 /s/ RANDI VAL MORRISON

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	CSKAUTO.COM, INC.
		
	By	 	 /s/ Randi Val Morrison

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary



  

 3 









			
	MURRAY’S INC. (successor to Fastlane Merger Corp.)
		
	By:	 	 /s/ RANDI VAL MORRISON

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	FASTLANE MERGER, LLC
		
	By:	 	CSK Auto, Inc., its Sole Member
		
	By:	 	 /s/ Randi Val Morrison

	Name:	 	Randi Val Morrison
	Title:	 	 Vice President, General Counsel and
 Secretary

	
	THE BANK OF NEW YORK TRUST COMPANY, N.A., as Trustee
		
	By:	 	 /s/ MELONEE YOUNG

	Name:	 	Melonee Young
	Title:	 	Vice President


  

 4