HVAC Professional Service Tool Kit:Dual Schrader Dell Valve Core Remover/Installer/Extractor/Changer & Port Service Ratchet Wrench Square Head+10 Core Replacements R410a R22 R134a refrigeration Dual size valve core remover installer change 1/4 and 5/16 inch port extract core in charged systems ratchet wrench for system port valve stem opening or closing port square head 4 sizes pack of 10 valve core replacements for all type of refrigerants in 1/4 and 5/16 system ports professional service tools sold in a convenient package kit alternative source for high quality service tools