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 asa 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.