1 6230: The smallest fret wire found on older Fender necks (.078″ x .043″). 2  6150: Vintage jumbo. Much wider but not as tall as 6230 (.102″ x .042″). 3  6105: Modern narrow and tall; currently very popular (.090″ x .055″). 4  6100: Jumbo. The largest fret wire available (.110″ x .055″).  6130: Medium jumbo (.106″ x .036″).