English: Panasonic-branded endless cassette for outgoing message in answering machines, 30 seconds. German-language labeling on paper sticker, but English-language endless embossed on the shell. The code KX-C030 was used by Panasonic throughout cassette era. The cassette is intended for single-side recording, and has simple but foolproof interlock to prevent playing the wrong side. Also, same interlocks prevent use of this cassette in any double-capstan deck (other brands' endless cassette often have provision for a second capstan).