This was the first thing that popped up on a Google search, but the ones that I use are from the same company but a little smaller with a different design (I use the Zerust Emitters):
ZERUST® Vapor Capsules are portable VCI emitter diffusers that contain VCI technology used to protect metals in hard-to-reach areas.
www.zerust.com
The ones I use come with double-sided tape and I have a couple where the shotguns/rifles are and a couple where the pistols are. Then I have 2-4 more between the various shelves where ammo or parts are. In conjunction with the Golden Rod, the humidity is pretty much nonexistent. When I am home and it’s ok to do so (no guests, kids, etc.), I’ll leave the safe door open when I’m working in the room the safe is in to get fresh airflow into the safe. It’s been working for me (along with regular cleanings - I’m that guy that enjoys cleaning his guns and cleans them frequently, even when not in use).
One important note is that the Zerust pods will yellow papers and effect pictures over time, so all of those items are in a “fireproof” bag in a separate safe within the gun safe to limit direct exposure to the Zerust.