Here is Fish Razr on their 4/0 Swivel Sleeves for Heavy Dredge Bars:
Swivels sleeves are used to add connection points to dredge bars and main lines in teasers. Simply put at the desired location and crimp both sides of swivel sleeve. When used with straight arm dredge bars you get the option of spacing the drops to your liking and adding the desired amount per arm. 4/0 work with our heavy barZ or 900 to 1000lb monofilament. The swivel has a 350 lb. test rating and the inside diameter is .150".
Made in the USA