Pros: Easy, inexpensive and humane way to repel tiny critters.
Cons: Replacement, since there are no working parts after a year or so.
Pest repelling products were always given a bum rap until Black and Decker proved that these little ultrasound products do work. If you live in an older building, a rural or woody park-like area near squirrels and mice or simply a cat and dog owner, you will truly appreciate the ability of these pest repellers to scare off fleas, spiders and most other kinds of creepy crawly things in from the garden, trees and unclean animals. I cannot vouch for other makers, but Black and Decker Pest Repellers work wonderfully so long as you leave them plugged in and the electricty going.
The devices come in six or three or even single packs, but you may want to own more than one depending upon the square footage of rooms. It is handy to place them on one side of the room and the other on walls that get a lot of possible ant, spider and other bug traffic. The cost for a 3-pack in Model 420 (the newer ones with an optional LED night light with switch) are only $16.90 which includes the shipping and handling.
The small white plug-ins use ultrasonic sound waves to disturb the critters into leaving the area. It does not necessarily kill them and emits no chemicals or toxins into the room. Like a grasshopper who rubs his legs together to get the sound waves moving to alert a mate, this product literally drives bugs and small rodents nutty and causes them to be disoriented and bothered enough in their nervous systems to leave the building.
This model is silent to humans and safe for use around dogs, cats, fish and small birds; however, you cannot use them near pet mice, hamsters, gerbils and the like. You can simply unplug them from time-to-time so that the bugs do not get too accustomed to the disturbance or to allow feeding of outdoor creatures that may come to visit your patio or deck.
In this day and age of "pestilences" and other super bugs that even science cannot account for, it is nice to know that science has also found a humane, inexpensive and easy way to fight back against Mother Nature. You can throw away all those harsh chemicals and body lotions that can cause serious damage to you and your pet indoors. This does not replace good grooming and cleanliness which are essential to any pest repelling routines, but it will help keep the critters from entering in the first place and asking politely those who enter to leave without too much fuss.
The night light feature is new and the switch on the side allows you to turn it on or off regardless of the main unit's operation. There is also an additional outlet so that it does not take up that outlet's ability for appliance plug in. You should not put anything over 110 power into the appliance however. You will not see any increase in your power bill since the useage is so low.
Black and Decker can be reached at 1-800-231-9786. They are independently tested in laboratories and have a little red light to tell you that the power plug-in is working. When the pests return, you will know it is time to replace the units after a year or two. The sound waves cannot reach under floors or behind walls, so you do not want to block these units with any big heavy furniture or storage bins.
The units require no maintenance and should be wiped with a dry cloth. I usually place mine near pet bedding, patio sliders and air conditioning units - anything that might seem inviting to the little buggers.