What are the most common sizes of wrenches, sockets/ratchet, nut drivers, etc that would be encountered in HVAC/R? Do you ever encounter metric stuff or just standard? I'm putting me a "jump" bag together and want to put the most used tools in it for less trips to the truck. I already have my electrical bag but want a second bag for wrenches, digital therm, etc. What contents would you guys recommend for a primary bag to "grab and go" to diagnose and make minor repairs or charge a system?