Almost 25 years ago we developed a glass frail for transporting glass on the outside of a van. This development was for glaziers who worked for glass companies.
Nowadays many of the glass frails we sell, install and service are for vans owned by window fabricators. The size of the glass units in their joinery has increased over time and they can no longer glaze in their factories, and have chosen to purchase glass frails (and other glass transporters) to get the glass from their factories to their customer sites to be site glazed.
For many years the industry knew it had to do more site glazing but was reluctant due to the extra time and cost incurred which would need to be passed to the end customer. The end clients wouldn't accept it. The workaround was to struggle and continue with factory glazing (and moving very heavy units to site), or do the site glazing and somehow absorb the cost. Fortunately this has mostly changed, and the costs of site glazing are an accepted part of the build cost.
There are still many window fabricators who contract out their site glazing, but increasingly we see the window fabricators employing glaziers and buying vans with frails to do the work themselves.
And that's how we came to sell more frails to window fabricators!