Z/Install Lite (a.k.a. ZI/Lite) is DOS software that creates self-extracting archives for software installation. It was developed by SpeedSOFT Development.
It includes ZPack Lite, a stand-alone utility for managing compressed archives in its native .ZPK format.
It's unclear whether non-"Lite" versions of these programs exist.
ZPK files (the non-executable kind) apparently start with bytes
01 5a 50 4b 01.
- Z/Install Lite v1.0 (DOS software)