It is a metal tool with a thin body and a diamond-shaped blade covered in Sun Flames.
By pressing it against the injury, the Saldatore del Sereno quickly heals wounds by activating the cells around the affected area, using the Activation characteristic of the Sun Flames. It has been shown to heal small wounds in seconds and even fatal injuries over time. However, forced over-activation may speed up and lead to cellular death. Tsunayoshi Sawada commented that the area around the wound itches afterward.
- In the post-chapter notes, it was incorrectly labelled as a Lightning-attribute Box Weapon.
- Another similar weapon has been mentioned in the series with the name Rain Trowel, which has the ability to tranquilize pain.