Seoul Semiconductor
Seoul Semiconductor Co., Ltd. is a Korean company that produces LED's. Their P4 and P7 LED's are used in a number of flashlights. The P4 uses Cree's EZ1000 die and has similar performance to the Cree XR-E LED. Do not confuse the Cree P4 bin (brightness) with the SSC P4 LED. P4 web page
P4 LED
The SSC P4 LED was much used as a "drop in" replacement for Lumileds Luxeon 3 LEDs. It gave about twice the output for about three times as long on the same battery and driver as a Luxeon 3. It had the same die height and beam pattern as the Luxeon 3 which the then new Cree LEDs did not.
P7 LED
The P7 is a multi-die LED utilizing four P4 LED's. P7 LED's have bin names that indicate brightness, color tint, and forward voltage. For instance a DSXOI bin indicates brightness level D, color SXO, and forward voltage of I. P7 web page
Brightness: Usually C or D where C is 700-800 lumens and D is 800-900 lumens (measured at 2.8 amps), but really there is some overlap where a low-end D might be less bright than a high-end C.
Color: A common cool white color bin is SXO, while SWO is more neutral, and SVN is warm. See this CPF post for a color chart.
Forward voltage: I and J are common. I is 3.25-3.50V and J is 3.50-3.75V, again with some overlap possible.
The dies are manufactured for SSC by Cree, but the phosphor is SSC's own. Many prefer the P7 to the Cree MC-E which has the same dies but different phosphors and lenses.