Seoul Semiconductor Co., Ltd. is a Korean company that produces LEDs. Their P4 and P7 LEDs were used in a number of flashlights though these are fairly old and do not appear to have been updated.
P4 LEDCree'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. 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 LEDP7 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 (6700K), while SWO is not as cool (6050K), and SVN is almost neutral (5350K). See chart below for all of the SSC tint bins and color temperatures, though not all bins on the chart are actually available.
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 optics.