We utilize a JIT (just in time) inventory system which is very common in the electronics industry. We invoice a group of customers to determine what exactly needs to be built and delivered by our contract manufacturer. Based on the types of radios ordered by the customers that were invoiced, we place a JIT order from our contract manufacturer, If your radio needs options, like an ATU, GPSDO or extended TX filter, they are installed in the radios, the chassis covers are installed and they go through final production test. We get the radios in-house and do an extra quality control step of verifying the radio you ordered has the correct configuration and then we do a physical inspection to check for any assembly imperfections and then re-run the final test and calibration software.
This allows us to build and deliver in a reasonable timeframe multiple models of radios with multiple configurations.
Even once we fulfill the order backlog, this is still how we ship from stock.