Selecting a harvester belt manufacturer requires more than matching an old belt by appearance. Agricultural OEMs and replacement-parts buyers need to verify belt dimensions, length references, pulley compatibility, machine information, and failure conditions before production. This guide explains what to include in an RFQ, how to use an existing belt as a replacement reference, why sample approval should precede larger orders, and what manufacturing, quality-control, packaging, and production factors buyers should evaluate when qualifying a supplier.