This is one of several sock blockers that I use. It was made by bending coat hanger wire into the desired shape and works well for laundering socks.
When I first needed a sock blocker, I couldn't find a commercial one that I liked. Now there are quite a few available on the market, but the ones I have work fine. My first ones were made of cardstock and were created to determine the size I needed. Then I used these cardstock patterns as templates to make polyethylene sock blockers in 2 women's sizes (medium and large). The polyethylene sock blockers were made from 1.5 mm thick stock, which is thicker than the plastic on binders.
Click on the thumbnail to view a larger image.