A set of 3 Telecaster bridge saddles machined out of solid brass.
These are the cylindrical barrel saddles, as found on the earliest Fender Telecasters. They have no notches or grooves, so that the string sits on the saddle entirely unimpeded. Many would consider this to be the optimal method for preserving the most of the string's natural characteristic.
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.