[Ron Foxcroft] made a wish list of features for a better whistle, and Foxcroft showed it to a plastics molding company in Stoney Creek, Ontario. They agreed to make parts for such a whistle if Foxcroft could present them with a design. They also recommended an Oakville, Ontario design consultant, Chuck Shepherd, who agreed to take on the project.

​The first prototype Chuck produced was louder and more reliable than a pea-style whistle, but too large and awkward. Undaunted, Shepherd worked with Foxcroft through more than 14 prototypes before at last perfecting the Fox 40 pealess whistle.

The Fox 40 whistle looked, felt and sounded very much like its predecessor, but worked on a very different principle. A pea-style whistle gets its shrill from the movement of the small cork pea in its interior, which alternately covers and uncovers the hole through which air is released. This process produces a rapid alternation of sound and silence, the characteristic whistle vibrato – until the pea gets stuck in the hole.

The Fox 40 Pealess Whistle is much like a harmonically-tuned instrument, because it produces three slightly different frequencies simultaneously. The different frequencies are superimposed on one another out of phase, and thus alternately reinforce and cancel out each other. The result is a loud, piercing vibrato that has no moving parts to get stuck. The whistle is a plastic-molded injection process that is ultrasonically welded together, rather than glued.

​The Fox 40 Pealess Whistle was a success from the first time it was used professionally, at the 1987 Pan Am Games in Indianapolis, Indiana. Ron Foxcroft was surprised to discover how far beyond basketball its appeal traveled – even the Indianapolis Police Department was interested in using this new whistle. The pealess whistle has become the whistle of choice for the National Hockey League (NHL), the National Basketball Association (NBA), the National Collegiate Athletic Association (NCAA), the National Football League (NFL), the Arena Football League (AFL) and the Canadian Football League (CFL). Fox 40 Pealess Whistles have since been used in numerous world-class tournaments, such as the Olympics and the World Cup.