This service increases delivery time by approximately one week. The 21852 is offered for customers who require calibration validation from an accredited calibration laboratory. When the 21852 is ordered, Campbell Scientific calibrates the data logger, and then sends the data logger to Simco Electronics in Salt Lake City, Utah. After Simco receives the data logger, they perform a calibration validation under the A2LA/NVLAP accreditation. Simco also provides a calibration certificate.