EXHIBIT 16.3 May 13, 2002 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Dear Sir/Madam: We have read the first six paragraphs of Item 4 included in Amendment No. 2 to the Current Report on Form 8-K dated May 10, 2002, of Merrimac Industries, Inc., to be filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, /s/ Arthur Andersen LLP ------------------------------ ARTHUR ANDERSEN LLP 4