Actually at Asia market, there are DVR-115, DVR-115D, DVR-115XL, DVR-115DXL.
Usually, some market sell the 115 black version (with DVD-RAM) as DVR-115BK, and the non-DVD-RAM version as DVR-115DBK.
At China, the version that has DVD-RAM read/write support has a suffix of “CH”, eg. DVR-115CH.
As usual, a “D” in the name means there is no DVR-RAM support on the drive.
The XL version support 12X DVD-RAM, come with a better looking facelet, and more sponge inside the drive to keep it silent, so it’s more expensive (approx. more USD$3~4 than the normal one). The black one has the name of DVR-115BXL.
Same story for the previous DVR-112…
CH = For China market
B = Black
D = No DVD-RAM
XL = Better Facelet + Silent
And one more, there is Pioneer DVR-112K in China market. It’s the drive made by Asus, and OEM by Pioneer (or the other way? I don’t know, I just read it). The DVR-112K support LightScribe and uses MediaTek chipset.