Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| For shank type | Singer part number | Uses templates? | Description | Storage case |
| --- | --- | --- | --- | --- |
| low | 86718 | no | ivory and red metal | red plastic box |
| low | 86721 | yes | 'Auto-Pilot' for zig-zag machines | cardboard box |
| low | 121795 kit 121908 buttonholer | no | old-style without a plastic body | cardboard box |
| low | 160506 | yes* | black metal body | green plastic box |
| slant | 102880 | yes | 'Professional', white plastic body | cardboard box |
| slant | 160743 | yes* | black metal body | maroon plastic box |
Question:
What's the singer part number of the buttonholer whose storage case is a green plastic box?
Answer:
160506.0