Figure out how many mm that length is. Then go to the dealership near you and get back to the belt rack. The belts have a mm listing on either them or the sleave. Since it's a 4 rib, they should have something in that tensioner range... that's how I found the OEMs for the UD pullies to begin with.
BTW, looking forward to installing mine... along with other goodies on the Z-Lab in the next couple weeks. :-)
Later
"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut." - Albert Einstein
When was the last time you *really* did something with your Z to call yourself a Z enthusiast?