A hot melt adhesive or other thermoplastic material metering system has different output assemblies interchangeably mounted thereon in a modular manner. In this manner, if it is desired to effectively convert a particular metering system from one type of metering system to another type of metering system, a particular output assembly can be exchanged for a different output assembly. In addition, if a particular output assembly needs to be replaced or repaired, the particular output assembly can be simply removed and a new similar output assembly can be simply installed.