I compared both pulley sets and Arrowhead Aluminum parts looked to thick...the cog count was too low:
While the MAS pulleys and belts looked MUCH better! more in scale I think!
So I bought two of the sets below ....BOTH sets are 10.00 USD each so it wasn't a hard choice.
They are in normal opperation ...but no longer taking 'ON LINE' orders.
Real nice folks!
Straighten up and fly right.....