Subclass of UnitField and returns a string response based on the annotated number.

  "type": "number",
  "field_id": "item_price",
  "title": "Item Price",
  "description": "Leave empty if not applicable.",
  "required": false,
  "use_slider": true,
  "min": 0,
  "max": 100
use_sliderbooleanfalseSet to true to use a slider instead of textbox.
minfloatundefinedSets the minimum value of the slider.
maxfloatundefinedSets the maximum value of the slider.
stepfloatundefinedSets the step value of the slider.