This heavy-duty pushbutton switch is the same 40 amp switch used in Longacre Pre-Wired Switch Panels. Mounts in a 5/8" diameter hole. The rubber cover has a 1.1" OD metal ring at the base.
Prevent accidental activation in crowded cockpits by adding a Push Button Switch Guard Collar, Part No. OMP-X/181493 (sold separately).