Ecolab (ECL) is the largest player in the industrial and institutional cleaning and sanitation business -- a sector that has outperformed the market by 20% since the beginning of 2007. It produces and sells products ranging from textile and silverware washing systems to detergent, vehicle-care and pest-elimination products. Restaurants, hotels, hospitals and schools are some of its largest customers, and it gains almost half of its revenue from abroad.

The company's primary advantage over competition is its scale, boasting $5 billion of the $47 billion of global sales in the fragmented industry. Its closest rival, JohnsonDiversey, has sales of roughly $3 billion, and it stopped providing direct service to its North American customers in 2006. This left Ecolab as the only provider with the resources to serve large customers in the United States. And while it engages in manufacturing and distribution, it's the company's direct service model that is at the heart of its success.

A motivated sales force earns as much as 75% of its compensation in variable pay, and it's these highly-trained reps that keep the company's products on order and functioning correctly. Customer retention hovers around 90% due to the outstanding service its sales people reportedly provide with regular calls. And while many of the products that it sells could be purchased through a number of manufacturers, Ecolab sets itself apart by providing customers with specialized equipment that's only compatible with Ecolab-branded products. The gear helps customers save money and makes switching to competing products more expensive.

Ecolab's scale, reputation for service and sustained customer relationships have helped it post consistent growth over the last decade. It recently reported strong third-quarter results with overall sales up 11% over last year on higher volume, pricing gains and foreign exchange benefits. Operating earnings per share were in line with the Street's estimates at 49 cents, though operating income slid 5% due to a $27 million charge for ongoing investments in the company's new business systems. It also acquired Microtek Medical Holdings for $274 million last quarter, and with its growing healthcare business, the purchase looks like a great strategic long-term play.