37 CFR § 2.126 - Form of submissions to the Trademark Trial and Appeal Board.
(a) Submissions must be made to the Trademark Trial and Appeal Board via ESTTA.
(1) Text in an electronic submission must be filed in at least 11-point type and double-spaced.
(2) Exhibits pertaining to an electronic submission must be made electronically as an attachment to the submission and must be clear and legible.
(b) In the event that ESTTA is unavailable due to technical problems, or when extraordinary circumstances are present, submissions may be filed in paper form. All submissions in paper form, except the extensions of time to file a notice of opposition, the notice of opposition, the petition to cancel, or answers thereto (see §§ 2.101(b)(2), 2.102(a)(2), 2.106(b)(1), 2.111(c)(2), and 2.114(b)(1)), must include a written explanation of such technical problems or extraordinary circumstances. Paper submissions that do not meet the showing required under this paragraph (b) will not be considered. A paper submission, including exhibits and depositions, must meet the following requirements:
(1) A paper submission must be printed in at least 11-point type and double-spaced, with text on one side only of each sheet;
(2) A paper submission must be 8 to 8.5 inches (20.3 to 21.6 cm.) wide and 11 to 11.69 inches (27.9 to 29.7 cm.) long, and contain no tabs or other such devices extending beyond the edges of the paper;
(3) If a paper submission contains dividers, the dividers must not have any extruding tabs or other devices, and must be on the same size and weight paper as the submission;
(4) A paper submission must not be stapled or bound;
(5) All pages of a paper submission must be numbered and exhibits shall be identified in the manner prescribed in § 2.123(g)(2);
(6) Exhibits pertaining to a paper submission must be filed on paper and comply with the requirements for a paper submission.
(c) To be handled as confidential, submissions to the Trademark Trial and Appeal Board that are confidential in whole or part pursuant to § 2.125(f) must be submitted using the “Confidential” selection available in ESTTA or, where appropriate, under a separate paper cover. Both the submission and its cover must be marked confidential and must identify the case number and the parties. A copy of the submission for public viewing with the confidential portions redacted must be submitted concurrently.