Been doing business with this company for the last year or so, and they have never let me down, the product is top quality and ones of the things that I appreciate the most is the prompt response to send what I have need.
I installed this on my Next SL crank and upgraded to the Sram XO1. I've put about 200 miles on the set up over some very technical terrain. I've not once had the chain come off. It's also very quiet even on the largest or smallest cog. As usual, BTD had the best price and shipped it out fast.