A set of 3 Telecaster bridge saddles machined out of solid brass.
As per the photo, they are not cylindrical as were vintage Telecaster bridge saddles, but instead have a modern modification to aid with the common intonation issues. The saddles are made with sloped tops to ensure that each string sits approximately where it should do for accurate intonation. This means that intonation will no longer be a compromise between the two strings that share each saddle.
Brass saddles are a popular upgrade from cheaper zinc saddles found on many Squiers and similar cheap copies. Brass is known, due to it's higher density than zinc, to provide more sustain, and thicker, more assertive tone.