This pack of 4 O-rings is used 2 at a time on your Fender System 1 arm, under the friction collar which adjusts the tension. The original clutch is a small white plastic ring. If yours is lost or worn out these O-rings are the proper size to function as a replacement clutch.
Without an arm clutch, the arm would dangle toward the ground and you would have to reach way down to grab it to use. With an arm clutch employed the arm will stay where you leave it.
Does not include arm or collar. Picture is for illustration purposes.