Newbie question regarding miter tracks, miter bars, t-tracks, etc

POWERTEC 2PK 36 HDPE Miter Bar for Table Saw Sled, Taper Jig, Miter Slot Runners, Fits 34 x 38 Slot on Table Saw, Router Table, Band Saw, Wood Working

The zero play guide bar system is a huge benefit for anyone making and using jigs in a climate where conventional wood…

miter slot Introducing the Miter Gauge Jig and Fixture Bar by POWERTEC This miter bar was designed to help your produce quality results when building jigs and

miter slot track ZeroPlay Miter Bars are adjusted to fit the miter slot while it is attached to your sled, allowing you to get the best fit possible Just set, test, and adjust