Dear Participant, We are pleased to present you with this Summary Plan Description (SPD) of the restated Plan. This SPD incorporates all improvements and amendments adopted in the IAM National 4 01(k) Plan through December 2021. The main purpose of the Plan is to give you the opportunity to save for retirement in a tax-advantaged way and to supplement your pension benefits and Social Security income. As a participant, you have an individual account with the Plan. You direct the investment(s) of your individual account, and your account will be adjusted every business day to reflect contributions, gains, losses, and expenses. You will be entitled to the balance of your account when you retire, become disabled, or otherwise leave employment or to an “in-service” withdrawal at age 59½. The Plan has many other valuable features: • Portability — as long as you work for an employer who has signed an agreement to participate in the Plan, you can participate; • Convenient, centralized administration; • Assurance of your voice in the program through your representatives on the Plan’s joint labor-management Board of Trustees. This SPD explains and summarizes the important features of the Plan. We believe that it accurately reflects the Plan document, the legal document that governs the Plan. However, the Plan document, as interpreted by the Board of Trustees, represents the final authority in all cases. If you have specific questions about the Plan as it applies to you, please contact the Benefit Funds Office or John Hancock, the Plan’s recordkeeper. Contact information can be found throughout, and on the back cover, of this booklet. Keep this booklet for future reference and let members of your family know where it is kept, as there are survivor benefits that may apply. If you lose this booklet, the Fund Office will be happy to send you another one. Sincerely, The Board of Trustees