Find a huge variety of Silicone Couplers & Boots you need to finish your project 2018-2021 Ford 3.0L Powerstroke. Find the coupler or boot you need with a variety of sizes from 2" up to 6" in diameter. These couplers are constructed with durable rubber or silicone and are reinforced for greater strength. To meet practically any need, a variety of couplers with straight, hump, reducing, and angled bends from 45 to 90 degrees are available. You'll find top brands such as Vibrant, PPE, Full Send, and Mishimoto brand products available at XDP.