The BU-P4289 is a BNC male to SMA female adapter typically used in radio frequency applications. The SMA end of the adapter uses a 1/4-36 UNS-2A thread.
The BU-P4290 is a BNC female to SMA male adapter. This 50 Ohm adapter is intended for use in radio frequency applications and has a maximum frequency of 12.4 GHz.
