Here is an image showing the pin diagram of this transistor.
Classification of hFE
The KSD1408-O transistor can have a current gain of 70 to 140. The gain of the KSD1408 will be in the range from 40 to 240, for the KSD1408-R it will be in the range from 40 to 80, for the KSD1408-Y it will be in the range from 120 to 240.
Complementary PNP transistor
The complementary PNP transistor to the KSD1408-O is the KSB1017-O.
SMD Version of KSD1408-O transistor
The BDP951 (SOT-223) is the SMD version of the KSD1408-O transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.
Replacement and Equivalent for KSD1408-O transistor