Unknown SIS shoulder strap insgnias

[No1canuck]

Hello, I stumbled upon these peculiar items and was wondering what they are. I am not even sure they are militaria. They appear to be some kind of bayonet holder? They each have a SIS pin that is inscribed, Made in Canada by Bond Boyd. I paid very little so I am not too concerned, just curious as to what they are. Any help would be much appreciated!

[NCA]

To me they look like epaulette slip ons.No idea what the initials stand for though..

[kradman]

Maybe from SIS Security ? worn by a Security guard

[Australia]

Maybe from SIS Security ? worn by a Security guard

I think so too .

[No1canuck]

Thank you for the help! Has anyone ever seen any in wear? Thanks!