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