I have one of these kits I found on ebay.
http://www.ebay.com.au/itm/Guitar-Ca...oAAOSwXeJXefZ2
The kit contains 3 double sided nut files.
-String winder with removable cup with electric screwdriver fitting.
-Light blue colored string height gauge.
-Small steel ruler with string spacing for various nut widths, you can see it quite clearly in the picture.
Now the nut files are VERY basic and you need to carefully read the string number stamped on the file - not the number on the colored plastic handle, they don't always match! - I found that out!