Their description:
Product Description
Nike + iPod Shoe Pouch enables you to use your Nike + iPod system on any sneaker lace. Lifetime warranty…. More >>
Go & get it here - i can recommend it:
Mivizu Nike+iPod Shoe Lace sensor Pouch for Nike + iPod Sport Kit
This product has been great for me and my husband. We can share the Nike+iPod between our iPods and shoes!