Using a highly controlled process, Du-Bro has devised a way to stabilize the Push Rod material so that neither heat nor cold has much effect on trim settings. In fact, in our tests, we found less growth or shrinkage than any plastic pushrod on the market. The red outer housing has 6 contact point giving the inner push rod a smooth positive control. Inner pushrod is translucent in color to better match your color scheme and give your model a more realistic look. 4 threaded rod slides inside inner pushrod to give a stiffer exit to control horn. Includes all hardware.