With regards to various aspects of installation, service, testing, and balancing, the DEWALTr HVAC Professional Reference is the number one pocket reference guide for the HVAC industry. Comprehensive coverage includes compressors, duct sizing, heat transmission conversion factors, temperature and pressure, fans, air velocities, refrigeration characteristics, thermostats, and much more. Compact but powerful, this handy pocket reference helps service technicians become experts on the job!