The search query, featuring a date (April 28, 2016) and "Caribbean" label, likely refers to a specific production identifier for Japanese model Yui Nishikawa [1.1]. Because these codes are associated with niche digital media catalogs, no mainstream, informative articles are available regarding this specific release.
The trailing numbers (-146 and -551) distinguish different specific scenes or sets released under that date's production batch. i--- Caribbean -042816-146- -042816-551- Yui Nishikawa