The chart provides the difference between the models and sizes.  The three features that set these two models apart and need further explanation is the Pen ID, Object Awareness, and OPS Expansion. The 6000 series displays have these features while the 4000 series does not.  The 4000 Series displays are icon driven, the user selects an icon to switch to the functionality that is wanted. 

Pen ID

Students can see their contributions free from interruption by their partner. Using different colored ink or creating different shapes, you can write or create independently and simultaneously in any lesson activity to open new collaborative opportunities.

SMART's first display with pen ID, allowing users to write in different colored ink, simultaneously, so you're not locked into the color choice of your partner.

 

Object Awareness

You already know how to use it. Offering the most intuitive experience by automatically differentiating between a finger, pen or palm, do what comes naturally. Touch, write, erase. Simplicity at its finest. 

OPS Expansion

The OPS Expansion is the expansion slot where the SMART Kapp IQ can be added.