I am the holder of a stock appreciation right (“SAR”) granted to me under the Casa Systems, Inc. (the “Company”) 2011 Stock Incentive Plan on 2 (the “Grant Date”) measured by the appreciation from and after the Grant Date in the Fair Market Value of 3 shares of Common Stock of the Company.

This Agreement evidences the grant by Casa Systems, Inc., a Delaware corporation (the “Company”), on , 20​ (the “Grant Date”) to (the “Participant”) of a stock appreciation right of the Company (this “SAR”) on the terms provided herein and in the Company’s 2011 Stock Incentive Plan (the “Plan”). This SAR represents the right to receive, upon exercise of such right, cash in an amount equal to the appreciation from and after the Grant Date in the Fair Market Value of a share of Common Stock, $0.001 par value per share (“Common Stock”), of the Company over the Measurement Price, as provided in this Agreement, with respect to the number of shares of Common Stock with respect to which this SAR is exercised. Unless earlier terminated, this SAR shall expire on , 20​ (the “Final Exercise Date”). All capitalized terms used herein and not otherwise defined shall have the same meaning ascribed thereto in the Plan.