Product review (4 stars): Decent safety solution
These do the trick.  They're not very sturdy, but neither is the price, so no complaints.  They are very easy to use and are a good solution to storing long blind cords so little ones can't reach them.  Best to use these to wrap up the bottom of the cord so you can grip the cord above these to work blind - pulling the cord below these can cause them to pop off or allow the cord to unwind somehow.