A guy that was used to horses and horse work, joined the Mounted Police.
However he found that had a lot of horses that weren't on duty due to back problems.

They came to the factory to see what saddle felt qualities and thicknesses were available.

They decided to get one saddle pad in both 19mm and 25mm thick to try out.
After numerous trials they decided on the 19mm, as this thickness gave enough padding between the saddle and the horse and the rider got a better feel of his horse, than with the 25mm thick pad.

They then order a complete roll of the 19mm saddle felt, cut to their pad size.
They then informed us that they just about got all the horses back to work, due to the success of the new pads.

Apparently after using a pad, they would bang it against a wall, or equivalent. It was then ready for another horse and saddle.

As horses have lumps and bumps in different spots, as too the saddles, they found the felt would go back to it original state, to make it ready for another horse.