This is the Traxxas 5460X GTR Hard Anodized PTFE Coated Shock Set.

PTFE-coated aluminum GTR shocks provide the ultimate in damping performance and control. A machined, threaded aluminum body with spring collar allows easy and precise preload adjustments. Vented spring perches help prevent dirt from packing around the X-ring seals. Shock shafts are coated in Titanium Nitride (TiN), making them harder and smoother for better scratch resistance, smoother performance, and longer seal life. Inside the shock, volume-compensating bladders ensure perfect damping throughout the travel range. GTR shocks are sold fully assembled in sets of four, complete with silicone oil. 

Springs sold separately.