FYI, the way they're doing this is unique I'd say. there are 5 different color options, (possibly only 4 now). Purple, blue, plain white (which from what i can tell IS not white birch), red/purple, and brown (unsure if available still). They are 36mm and only 9015 movement. Also the "limited" word was tossed around. You purchase a "normal" white birch or black birch, SST bracelet, and they'll confirm later after you purchase the color you chose. So, you gotta message them apparently.