25 Pa. Stat. § 3146.4
The county boards of election shall provide two additional envelopes for each official absentee ballot of such size and shape as shall be prescribed by the Secretary of the Commonwealth, in order to permit the placing of one within the other and both within the mailing envelope. On the smaller of the two envelopes to be enclosed in the mailing envelope shall be printed, stamped or endorsed the words "official election ballot," and nothing else. On the larger of the two envelopes, to be enclosed within the mailing envelope, shall be printed the form of the declaration of the elector, and the name and address of the county board of election of the proper county. The larger envelope shall also contain information indicating the local election district of the absentee voter. Said form of declaration and envelope shall be as prescribed by the Secretary of the Commonwealth and shall contain among other things a statement of the electors qualifications, together with a statement that such elector has not already voted in such primary or election. The mailing envelope addressed to the elector shall contain the two envelopes, the official absentee ballot, lists of candidates, when authorized by section 1303 subsection (b) of this act, the uniform instructions in form and substance as prescribed by the Secretary of the Commonwealth and nothing else.
25 P.S. § 3146.4