Meaning of LED Designations (TWOH, TWOJ, etc.)

Could someone please point me to a thread or other article that gives a basic explanation of the meaning of the different designations of LED emitters---TWOH, TWOJ, etc. That is, what does each letter designate?

Thanks.

Very basic explanation: First letter (S,T, etc.) is the brightness at a given level of power- that is, a higher letter means the LED is putting out more light for the same power; it's more efficient. The second 2 letters (WO, YA, etc.) are the tint of the LED for a white emmiter (closer to blue, yellow, etc.- Lumiled has a segmented color chart). The last letter is the range of forward voltage (vF) that the LED should be driven at- Lumileds specifies a minimum and maximum voltage for each bin to be driven at spec (a higher letter means more voltage will be need to drive at spec, but also, the LED will tolerate a higher voltage without frying). There is a "bin codes explained" thread somewhere on CPF that you can find for more info.

Thanks, guys. Very helpful.

I have a single-page summary of Luxeon binning in my signature - see "Luxeon binning."

Obviously a lot of those codes are there for future use...
So what are the brightest and most efficient bins available now or in the near future? For example are there U or V flux bins for sale anywhere?

Photonfanatic I think still has some UX1L bin Luxeon3's
in BST Lights Forum.