This slide shows an example of Johanson’s part numbering scheme. In the part number 2450AT45A100, the first four digits, “2450”, represent the center frequency of operation (in case of the dual band antenna, these digits represent the lower band frequency). The following letter, “AT”, designate the antenna family (dual band antenna is defined by letters “AD”). The next two digits, “45”, represent the case size. The “A” designates the version of the antenna and the last three or four digits denote the bandwidth (in the case of the dual band antenna, the last digits represent the higher band frequency).