From the product:
"The Svirfneblin Effect" is an encounter that may be inserted into any existing dungeon or played as a brief standalone adventure.
The deep gnomes are building a dangerous apparatus and worshiping an even more dangerous idol. Can their dark plans be thwarted?
For levels 5 to 7, "The Svirfneblin Effect" is designed for First Edition but may be played with any OSR product line (OSRIC, S&W, OSE, et cetera).