Post Meta field-number
1 . Field Label : Field Label as well as Field title
2 . Field Type : Field Type List (You have already selected ) . Use it if you need to change field type
3 . Meta Key : Set Unique MetaKey for field (e.g. book_author)
4. There are two check-box => Required => Allow Duplicate
5 . Field Size : Set field size as well as field width (e.g 200px)
6.Field Help Test : If you wat to give some help text for field then use it (e.g. Number only)
7 . Field Class : You can define extra class for field
8 .Maximum Number : Set your maximum number (e.g 20)
9 .Minimum Number : Set your Minimum number (e.g 2)
10. CSS Style : Field Style ..(e.g. color:red;display:block;)
11 . Use it for delete field