Eva-Dry Wireless Mini Dehumidifier, White (E-333)

Why it's worth it

A cordless silica gel unit that sits or hangs inside the safe and pulls moisture out of the air with no power at all. Colored beads turn pink when it's saturated, and you plug the whole unit into a wall for eight to ten hours to reset it.

If you rent, or your safe has no knockout hole, this is the one that works. No drilling, no cord routing, no outlet near the safe. You put it inside and close the door. That covers a lot of people — apartment dwellers, anyone with a safe bolted into a closet, anyone who bought a cabinet that never had a knockout to begin with.

The color indicator takes the guesswork out. The silica gel beads start blue and turn pink as they saturate. You're not tracking dates on a calendar or weighing anything. You glance at the window, and if it's pink, it's time to recharge. That's a genuinely better maintenance experience than desiccants that give you no signal at all.

From our review of 8 gun safe dehumidifiers, by David Sinclair, Managing Editor

What we like

• +If you rent, or your safe has no knockout hole, this is the one that works
• +The color indicator takes the guesswork out
• +Coverage and cycle length are realistic for a small to mid-size safe
• +It's non-toxic and there's nothing to spill

What to know

• –Recharging means the safe goes unprotected for most of a day
• –One unit isn't enough for a big rifle safe