RJ-Sport | Heavy Duty Cord LocksRJ Sport Heavy Duty Cord Locks ord locks are a great solution to keep your strings in place, whether they be drawstrings or laces. The determine factor of a cord lock is its gripping power, thats why RJ Sport Cord Locks use premium stainless steel spring. You may notice they are a bit harder to push when youre threading the cords, but they do grip a lot better. FAQ Q: How to put these on shoelaces? A: Press the button down and hold it while threading