Sprocket specilists has to import their product and last time I called they where just plain out fo product and said it'd be 2-3 month before they got it in.  I did run one of ther aluminum ones with the special coating that cost me over $100 and it lasted 2 seasons in the sand.

Went back to the OEM sunstar steel ones and I'm going on season 4 with this one.

JT is good and primary drive is rocky mountain ATV and they seem to last for the friends that are running them.