1. Sheet of steel (purchased at Lowes). There are many different sizes available, choose the one that best fits your need.
2. Toggle bolts (purchased at Lowes). The spice rack needs to be anchored to the wall if you're putting it into drywall. Mine we're 3/8".
3. Super Glue. I used E-6000 (purchased at Walmart?). The only thing I did not like about this was the drying time. At LEAST 16 hours. It was also stringy and had a tendency to get everywhere, although it did not become tacky right away, so that was good.
4. Neodymium magnets (purchased from eBay). I used 1/4" x 1/16". Next time I would go larger in diameter because I ended up having to use two magnets in order to make a full jar stick to the steel.
5. Spice Jars (purchased online). This is totally up to you. Personally, 4oz is PLENTY big enough. I probably would've gone for 2oz jars, but I couldn't find the shape I was really going for in 2oz (hex shape).