First Supplemental Indenture, dated as of October 26, 2016, by and among Leslies Poolmart, Inc., Leslies Holdings, Inc., the other guarantors party thereto and U.S. Bank National Association, as Trustee

Exhibit 4.2

First Supplemental Indenture

THIS FIRST SUPPLEMENTAL INDENTURE, dated as of October 26, 2016 (this “Supplemental Indenture”), is by and among Leslie’s Poolmart, Inc., a Delaware corporation (the “Issuer”), Leslie’s Holdings, Inc., a Delaware corporation (“Holdings”), the other guarantors party hereto (the “Guarantors”), and U.S. Bank National Association, as trustee (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Issuer, Leslie’s Holdings, Inc., a Delaware corporation, the other guarantors from time to time party thereto and the Trustee are parties to an indenture dated as of August 16, 2016 (the “Indenture”), providing for the issuance of the Issuer’s Senior Unsecured Floating Rate Notes due 2024 (the “Notes”);

WHEREAS, Section 9.2 (Amendments With Consent of Holders) of the Indenture provides that the Indenture and the Notes may be amended or supplemented with the consent of the Required Holders, which consent has been obtained with respect to this Supplemental Indenture; and

WHEREAS, pursuant to Section 9.2 (Amendments With Consent of Holders) of the Indenture, the Trustee is 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 Issuer, Holdings, Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders as follows:

1. Capitalized Terms. Capitalized terms used herein without definition will have the meanings assigned to them in the Indenture.

2. Amendments to Indenture.

(a) Section 3.4(b)(xx) of the Indenture is hereby amended to replace “clause (27)” therein with “clause (28)”.

(b) Section 6(a) of Exhibit A to the Indenture is hereby amended to replace “August 16, 2018” therein with “August 16, 2019”.

3. Amendments to Notes. Section 6(a) of the outstanding Note designated as Note No. A-1 is hereby amended to replace “August 16, 2018” with “August 16, 2019”.

4. Ratification of Indenture; Supplemental Indenture 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 will remain in full force and effect. This Supplemental Indenture will form a part of the Indenture for all purposes, and every Holder heretofore or hereafter authenticated and delivered will be bound hereby.

5. No Recourse Against Others. No manager, managing director, director, officer, employee, incorporator or holder of any Equity Interests in the Issuer, any Subsidiary or any Parent Entity, as such, will have any liability for any obligations of the Issuer under the Notes, the Indenture or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each Holder of Notes, by accepting a Note, waives and releases all such liability. This waiver and release are part of the consideration for issuance of the Notes. This waiver may not be effective to waive liabilities under the federal securities laws and it is the view of the SEC that such a waiver is against public policy.

6. Governing Law. This Supplemental Indenture will be governed by, and construed in accordance with, the laws of the State of New York.

7. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy will be an original, but all of them together will represent the same agreement. Delivery of an executed counterpart of a signature page to this Supplemental Indenture by telecopier, facsimile or other electronic transmission (i.e. a “pdf’ or “tif’) will be effective as delivery of a manually executed counterpart thereof.

8. Effect of Headings. The section headings herein are for convenience only and will not affect the construction hereof.

9. The Trustee. The Trustee will not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Issuer.

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

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture