Formerly known as the STANLEY TSTAK™ range, STANLEY has renamed the system and expanded the line-up to meet the demands of an even greater number of professional trades.
Furthermore, the new PRO-STACK™ storage series is fully compatible with the existing STANLEY TSTAK™ range. PRO-STACK™ and TSTAK™ units are interchangeable and can be used with one another as part of a universal storage system.
Had to google it.
Are you sure it's dying? Maybe you're just not finding any because they changed the name.