No tools necessary. This is a top quality product that can be used by anyone in need of dryer connections. Just pre-assemble the 90-degree elbow, attach it to the vent and the dryer, and it’s ready for immediate use. No hose clamps required. Snugly attaches the hose and dryer with a secure seal. The flexibility and angle allows the pieces to fit properly and hug the wall when placed against it. The elbow is 5.55 inches wide. The opening where it attaches has a 4.08” diameter without the clear silicone seal, and 3.96” with the seal ring. Made in USA by Ziggurat Products.