Hi WK4U of Roswell:
IEEE 802.11 WEP comes in two sizes, WEP-40 and WEP-104, which use fixed length keys of 40 bits and 104 bits respectively.
40 bits can be represented by 10 hexadecimal 4 bit digits, or by 5 ASCII 8 bit digits. 104 bits can be represented by 26 hexadecimal 4 bit digits, or by 13 ASCII 8 bit digits. Usually hexadecimal is used to both enter and display WEP keys.
The numbers 40 and 104 appear strange choices for binary work, until we remember that a 24 bit WEP initialization vector is used with both to give us the familiar numbers 64 and 128.
I hope this helps. Thanks. /criss