Beaded stretch bracelets (and finger rings) are economical and easy to make, and they're great projects for adults and kids alike. When you shop for stretch cord for your bracelets online or at a well-stocked bead store, you'll discover that you have several options. Here are the two most important factors to consider when deciding which to buy.
Stretch Cord Size
It's important to select cord that will hold up to your beads and won't break prematurely. When it comes to durability, cord size is typically the most important factor. Select your beads before you select your cord, and then buy the largest cord that will fit through all of them when doubled over if you plan to use a needle, or singly if your beads are large enough to string without a needle.
Checking the fit is easiest if you buy your supplies at a local bead store. Most stores will allow you to test a package of cord on your beads, or they'll have a sample of cord at the counter that you can experiment with. When you're ordering online, check to see whether your beads' hole sizes are listed in their item descriptions, and select cord that is just slightly smaller. For most seed beads (size 11/0 or 8/0), I use 0.5mm cord, which I use with a collapsible-eye needle.
Types of Stretch Cord
There are three popular types of stretch cord. The first (and probably most common) is rubbery, translucent cord made up of a single strand. One popular brand is Stretch Magic. This cord comes in a wide range of sizes, including large sizes, and I often use it with large beads. It's downside is that it can be slightly more difficult to knot tightly than other types of stretch cord.
A second type of cord I use often is called stretch floss. It's available in a variety of colors but not a lot of sizes. The most common sizes you'll find are 0.5mm and 0.7mm, which are suitable for most smaller beads. Stretch floss is made up of multiple strands of stretchy material woven together. This gives it good stretch "memory" (meaning that it's less likely to permanently stretch out) and makes it easier to knot than most single-strand cord.
The third common type of stretch cord is polyester cord with an elastic core. The polyester that coats this cord is available in a wide array of colors, including sparkles and metallics. This type of cord is often used for hair accessories or other applications where the cord will remain visible in the finished design. You can also use it for stringing larger beads; but because of its bulk, its knots may be a little harder to hide.