The Squealer is a true motion-detecting flange squeal system. Using professionally recorded and edited flange squeal, The Squealer brings authentic trackside sound of steel wheels against rails for ultimate realism. The system uses a micro motion detector between the ties to sense train movements and play either the built-in professional sounds or user-defined sounds for maximum flexibility. Modelers now have the ability to recreate all the trackside audio ambience that has been missing from our model worlds.