We’ve streamlined the process and revised the design of the K Series Ultra Fuel (350-05-7000) to replace the Ultra Fuel Rails listed below.The Skunk2 Racing K Fuel Rail is the perfect compliment to the Ultra Street Manifold and especially the Ultra Race Intake Manifold with its dual injector positions. This K-Series Fuel Rail is used for both the primary injector position and the secondary injector position. One rail, two positions. 350-05-6050 DISC- K ULTRA RACE PRIMARY BLACK , 350-05-6055 DISC - K ULTRA STREET FUEL RAIL , 350-05-6060 DISC- K ULTRA RACE SECONDARY BLACK , 350-05-6070 DISC- S2K ULTRA RACE SECONDARY BLACK