It's Schrader access valve allows you to

                check and adjust the coil's superheat.

Cooltube has both the thermal expansion valve and schrader access valve outside of the evaporator and are located next to each other.  This makes it fast

and simple to set the evaporator's superheat with

the refrigeration system operating without taking

the evaporator apart. This will make checking and setting the superheat faster with great accuracy.

Cooltube's externally installed thermal expansion valve and suction lines must be insulated as shown.