system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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after its expiration date. 3.6. Packaging and Labeling. The Products shall be delivered by Qualigen, and Sekisui shall cause the Products to be delivered to end users, in Qualigen packaging and with Qualigen labeling, all as intended to be received by the end user. Such packaging and labeling (and the Products themselves) (and "product inserts," which Qualigen may provide online so long as it is done in compliance with all legal requirements of the applicable jurisdiction) shall include such Qualigen trade names, brand names, trademarks and logos (and patent notices) as Qualigen shall select and with such size, colors, positioning and prominence as Qualigen shall select in its sole discretion, and shall not include any Sekisui trade names, brand names, trademarks or logos (except that, if so required by applicable law, Qualigen shall include a statement that Sekisui is the distributor and/or that Sekisui is the importer). Sekisui shall not imprint or affix any of its (or any non-Qualigen person's) trade names, brand names, trademarks or logos to any Product or its packaging or labeling, and shall also cause its subdistributors not to do so. Sekisui shall not deface, cover, obscure, erase, alter or remove any Qualigen trade names, brand names, trademarks or logos (or patent notices) applied by Qualigen to the Products or to the Products' packaging or labeling, and shall also cause its subdistributors not to do so. 5 Source: RITTER PHARMACEUTICALS INC, S-4/A, 3/13/2020 4. Price, Shipment and Payment 4.1. Price. The price that Sekisui shall pay for the Products shall be established separately for the Reagent Kits and for the products other than Reagent Kits. The price that Sekisui shall pay for the Reagent Kits Products shall be based upon a formula intended to ensure that Sekisui will receive 90% of the total Available Margin for all Products during the first 12 months of this Agreement, 70% of the total Available Margin for all Products during months 13-24 of this Agreement, and 65% of the total Available Margin for all Products thereafter. Accordingly, the prices (established separately for the Reagent Kits and for the products other than Reagent Kits) to be paid by Sekisui for the Products shall be fixed (subject to a later lookback true up) for each respective prospective six month period in the manner set forth in Exhibit D. The initial prices Sekisui agrees to pay for the respective Products for the first such prospective "six month period" (in this instance actually a five month period: May-September 2016) shall be fixed (subject to a later lookback true up) in the manner set forth in Exhibit D. Thereafter such prices shall be revisited and recalculated (prospectively) every six months in the manner set forth in Exhibit D (i.e., for purposes of such calculations for establishing the new prospective prices for the reagent products, the applicable Net Revenue, COGS and Available Margin shall be the Net Revenue, COGS and Available Margin for the applicable historical 6-month period as defined in Exhibit D). In addition, on a semi-annual basis, such amount shall be reviewed based on the actual Net Revenue, COGS and Available Margin for the 6 months then ended. In the event that such review results in a difference from the intended share of Available Margin between the Parties as contemplated above, the Parties shall make a true up payment between them in order to compensate for such overpayment or shortfall, all as provided in Exhibit D. Any true-up payments shall be paid by the applicable Party within 30 days of the receipt of an invoice for the agreed to true up amount. Sekisui shall set the customer selling prices in good faith and in a commercially reasonable manner. 4.2. Shipment. The shipment of orders to Sekisui's customers shall be subject to the ability of Sekisui and Qualigen to obtain all required licenses and permits then in effect. Qualigen agrees (i) to assist Sekisui in obtaining such required licenses or permits, (ii) to comply with all Regulatory Approvals in, including all approvals and licenses necessary to import the Product into, the Applicable Markets, and (iii) to maintain the necessary records to comply with all Regulatory Approvals and other applicable rules and regulations in the Applicable Markets. Qualigen shall not be subject to unreasonable requests for assistance in applying for Regulatory Approvals such as providing original or proprietary documents, submitting free product samples or extensive translations. All Product ordered by Sekisui's customers shall be suitably packed for shipment and storage by Qualigen on behalf of Sekisui
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Extract the exact clause related to "Irrevocable Or Perpetual License" from the excerpt above.