What is an shk file?

[dgalway@calvin.stemnet.nf.ca (Dennis L. Galway)]

I am a Mac user.  However, In my school I am responsible for a computer
lab that has 16 networked IIgs computers and I am also responsible for
as many stand-alones.

I would like to download some freeware and shareware for these
computers. However, I am unfimiliar with shk files that are available at
Apple II ftp archives.  I assume that an shk file is a compressed file.
Could some out there inform me as to the nature of this file type and if
it is a compression utility, where I can obtain the utility to expand
shk files.

Thanks in advance.
--
Dennis Galway
Grade 6
Amalgamated Academy
Bay Roberts, A0A 1G0