The Kirby Sentria is the best investment I have ever made! I learned so much from the demonstration and everything I learned I researched and found to be very true. In many studies by vacuum professionals the Sentria out cleaned every vacuum, sometimes by as much as 3 to 4 times better. It even cleaned 3 times better then a Dyson. Nothing can get sand and grit out from under the carpet padding but the Sentria. I clean my matteress once a month, I no longer get sleepys in my eyes or wake up with a stuffy nose. It eliminated the dust mites all together. I have 2 dogs and 4 cats and there is never...