These work so well in my house that I just ordered a second one after having mine for a year. It has held up perfectly well and I want another one to place in other areas of the house. First, the design: the whole trap measures approximately 8-9 inches long by 3-4 inches wide. There is a plastic covering on the top so you can see inside easily. There are ventilation holes on 3 of the sides so the mice can smell the bait and breathe when they are caught in it. (I have previously used the Mouse Cube which has practically no ventilation so the mice become wet and can't hold up as long waiting to be found. I much prefer this well ventilated design of the little Pete.) Inside are two covered ramps that are held in place by magnets on the bottoms. The mice climb up the little ramp and when they get to the inside end, the other end closes because of their weight on the see saw, so they cannot get back out. Once the mice are released it is very easy to open up and take apart to clean. The lid closes tightly so there is no way they can push their way out the top. Baiting: although the description says you don't have to bait them, you are going to have much better luck if you do. I have gotten my bait down to a science. First, I rip a paper towel in half and then fold it the long way until it fits inside the main part of the trap. This makes it much easier to clean the trap later on! Otherwise their droppings and urine dry to the metal and requires a good scrubbing. It also gives them something to keep warm in, especially important if your traps are in a cold area like a garage. For food, I use something with a strong smell like sugary cereal, salty corn chips, seasoned croutons etc and sprinkle some grated parmesan cheese (very stinky!) over it all. I have found that when it comes to catching mice, the stinkier the bait, the better to attract their attention! Don't be stingy with bait either! The more you have in there, the more likely you are to attract multiple mice. Plus they then have plenty of snacks to munch while they await their release. Then I use a tiny dot of peanut butter on each beginning and end of the ramps, so there are two dabs of peanut butter on each ramp, I believe this helps them find their way in. Placement: mice do not tend to like open spaces, so placing the trap along a wall or behind something works best. Mine sit either behind my microwave or coffee maker, or along the back wall of the cabinet under my sink. Try to place the traps in areas where you tend to find the most droppings. Check often: the first time I set up my trap, I caught four mice in a matter of hours! They tend to be most active at night, so I always check before bed and first thing in the morning. (The description says it can fit 10, but I think that is an exxagerated number. I believe it to be closer to 4-6, looking at the space on the inside of the trap.) Release: Mice can find their way back easily, so make sure you get in the car and drive them somewhere miles and miles away. I drive mine to the river and release them in a hollow log that I found near the parking area. It is common courtesy to let them go where there are no houses around, if possible for you. Otherwise they will just become someone else's problem. Open up the top of the trap and set it down, they usually hop right out, or sometimes I have to give the trap a bit of a shake to encourage them to jump out. I always wish them well and wave goodbye as they scamper away to their new home. Cleaning: I clean the trap between each release, before I set it back up. I just take the ramps out, dump the paper towel with the leftover food and droppings in the trash or fire pit, then wash and dry the inside and outside of the trap and ramps with tea tree oil cleaner. Put it back together and start all over! Troubleshooting: If you find that you are not catching any more mice, try changing the type of bait you use. I rarely use the same bait twice in a row. Remember, the stinkier the better, even if that means hard boiled eggs! They also seem to like sweets like chocolate. Also, change the area that you are placing it. If it doesn't work on one end of the counter, move it to the other end. I have found that every time I stop catching them, simply moving the trap by a few feet and refreshing the bait does the trick! Summary: I am very happy to have found such an effective trap that doesn't require me killing innocent creatures. I don't want them dead, I just don't want them pooping on my stuff. This trap allows me to spare their little lives easily and let them live out their days in the wild where they belong. I would highly recommend these traps to anyone. I will not ever buy another type of trap again. They are built to last, they are easy to set up and clean, and THEY WORK.