Japanese AV labels use highly specific date-coded or serialized identification numbers. In this instance, "042816" points directly to a release on April 28, 2016. The trailing digits isolate the exact video from that day's schedule.
The provided numeric strings and 042816551 are identifiers for specific video content released by the Japanese production company Caribbeancom . These releases feature the Japanese actress Yui Nishikawa caribbean 042816146 042816551 yui nishikawa patched