There's a clutch at the front end so when the AC is off there is little power loss as this behaves much like an idler pulley.
But I doubt anyone has the belt specs so you will likely have to go at this the old fashioned way. It uses the usual cloth tape measure. I see this site describe the process.
OK, so now you have the outside length and just need to find the belt type or code and see if you can find it.