With the temperature hovering in the mid-90s, a lone truck driver hauled a few big boxes into a nondescript building. They held just what the folks inside had been waiting for: winter coats.

The coats, ranging from hot pink to camouflage, were needed so that the company could . . . get down.

Literally.

"I have a neighbor of mine who used to run along the street, and he used to think for sure this building was a front for the CIA or the Mafia, that there in no way could be a feather and down laboratory," said Wilford Lieber Jr., president of the International Down and Feather Laboratory & Institute.

But not only does the building house such a lab, it's no featherweight in the field. The Liebers — Wilford Lieber Sr. is chairman of the board — say their Salt Lake-based operation rules the roost as the world leader in the testing of down and feathers used as fill material in pillows, bedding, apparel and other products.

A downpour of about 6,000 samples a year comes through the doors, and summertime is the most hectic.

"The busy season for us is right now, where everybody in the world is manufacturing products for this coming fall," Lieber Jr. said.

After the downloads from the truck, the items — from bulk bags of fill material to finished products — undergo a rigorous compositional test. In the case of the delivered coats, they'll be cut open and dissected. The idea is to ensure that what's on the labels is exactly what's inside. Other analyses can check "fill power," cleanliness and other criteria.

Those "Do Not Remove Under Penalty Of Law" tags on filled items spell out the exact percentages of the innards, and IDFL checks to ensure there's nothing loosey-goosey with the claimed figures.

Customers flocking to IDFL include down and feather producers — most are in China, where the washed and sanitized material is a byproduct of the food industry — plus manufacturers of filled items. Retailers also have tests conducted to ensure they're selling properly labeled merchandise. And government agencies call on IDFL when they do random compliance checks on products.

"There are so many people involved, and they all have the checks done along the way," Lieber Jr. said. "You don't want contamination or somehow if the down is sitting on a dock somewhere that it's dirty in shipping, so it's always checked."