Similar to ABL variables, properties in class files maintain data or state. Like a data member in a class, a property can be defined with an access mode (PUBLIC, PROTECTED, PRIVATE) that determines where it can be read or updated. Properties are PUBLIC by default.

But unlike ABL variables or class data members, properties can be defined with a GET accessor and/or a SET accessor for reading and writing a property's value, respectively. These accessors, which are blocks of ABL statements, can contain code which is executed when the property is read (GET) or assigned (SET). If either the GET accessor or the SET accessor is omitted, the property is defined as write-only or read-only, respectively.

While there is no direct equivalent to properties in traditional ABL, properties can be simulated in persistent procedures, for example in the ADM2, by defining user-defined functions that control the reading and writing of an ABL variable.