If your guitar saddles are too small (narrower than what the bridge requires), then there will be gaps between the saddles. When this happens, and especially if you’re using the tremolo bar, the saddle can move out of place while playing – which makes the guitar go out of tune. See video.
What if the saddles are wider than the specification?
If your saddles are a little wider than the bridge specification, they will still fit as long as they’re within 0.12mm. This microscopic variance is called industrial tolerance and is invisible to the naked eye.
For example, if your guitar bridge requires a 10.5mm saddle, and your replacement saddles are 10.6mm, they will work. In this case, your saddles will fit snugly against each other and will not move out of place.
Also, Audible Steel saddles are smooth on top (there’s no notch) which allows the string to remain in a straight line between the saddle and the nut. Therefore, it will not go out of tune.