Brass Kit: Comes with all materials (Base, Yoke, Springs, Pole, Sleeve, Dummy Wheel, Dummy Slider, Base Support). All streetcars had some form of trolley pole and base on them; this is a US-23 two spring type base. There were several types and styles of trolley bases. The US 23 was not all that common, but probably used throughout the industry. The wheel and slider are also a common item, and many of these were fabricated in the company shops, and they may have had different size wheels, etc… Some cities (Philadelphia for one) used trolley wheels until the mid to late 1980’s. In later years, a trolley “shoe” using a carbon block for the current pick up, was used and still is used in many cities today. Or they have switched to the more modern Pantograph.