Hi-Tek 725 Switch (Space Invader Switch)
Hi-Tek Series 725 was Hi-Tek Corporation's DIN-compliant keyboard series, introduced in 1983; the name refers to how these keyboards are a maximum of 0.725″ from the desk surface. “Series 725” also refers to the switches used in these keyboards.
2018-09-26 from https://deskthority.net/wiki/Hi-Tek_Series_725
Hi-Tek 725 Key Switch is used in Revision A of Symbolics keyboard PN 365407