Commodore Datasette 1531

The successor of the 1530 had a different connector for the Commodore 16 (and Plus/4) and had the same colorscheme black.

1531 was only usable on the C16/C116 and Plus/4
It has a special connector for the C16 and Plus/4

Information:
https://www.richardlagendijk.nl/cip/datassette/item/1531/en
https://www.c64-wiki.com/wiki/Commodore_1531
https://en.wikipedia.org/wiki/Commodore_Datasette