This is so 90's:

Introducing the FIRST SAFE and TRANSPARENT way to double your disk
capacity... because you're going to need it.

Doubles Your Disk Capacity. We call it Stacker. You may call it magic.
But with a few mouse clicks you can double the capacity of any
Macintosh� hard disk. Install Stacker once, and you never have to
think about it again. Our patented Stac� LZS? technology automatically
stores your data more efficiently so you can put more data on your
disk. It's that simple. So it's not really magic ? it's just smart.

 * Doubles hard disk capacity
 * Foolproof installation
 * 100% compatible with all INIT's, disk utilities? including disk
   recovery programs and hard disk formatting software
 * Supports all hard disks and the majority of removable cartridges
   such as SyQuest�, magneto-optical and Floptical
 * Stacker Anywhere?? lets you use your hard disk or removable
   cartridge on any Macintosh ? no additional software is required
 * Stacker Autoprotect? Automatically detects problem with your data.
   Includes data recovery capability
 * Remove Stacker? Returns your hard disk or removable to its
   original condition.
 * Online and Balloon Help
 * Supports up to two gigabytes of Stacker disk capacity

Since hard disk space is not an issue anymore, this is just a survivor
of that era when hard disk was very expensive and you needed to
squeeze every bit of space out of your hard drive. Perfect for those
with vintage macs with vintage small hard disks.

Compatibility
Architecture: 68k PPC

System 6.0.8 or greater, Mac Plus or higher with SCSI disk drive, 2
megabytes of RAM