4The HVAC/R professional reference contains more than 500 pages of extensive information on such important topics as refrigeration systems, piping, ductwork, motors, compressors, fans, pumps and more. Practical troubleshooting techniques and service call procedures for understanding and maintaining all heating and cooling systems are featured. Ample safety coverage and the inclusion of plan symbols, materials, and conversion factors round out the exceptional features of this "must have" pocket reference. Check out our app, DEWALT Mobile Pro(TM). This free app is a construction calculator with integrated reference materials and access to hundreds of additional calculations as add-ons. To learn more, visit dewalt.com/mobilepro.