Magnetic clasps are very strong, easy to attach, and easy to open and close.   They are composed of two pieces, each with an embedded magnet.   Each piece has a loop from which you attach the string of beads.

If using on a bracelet, we suggest adding a little safety chain (2-3" of chain, or a chain extender piece)

Opening and Closing Magnetic Clasps: This is a bit trickier than you might think.
For the simple, plain clasps, you would slide these together and slide them apart. For the fancy ones, you break these open, like breaking a stick. Pretend that one side has a hinge, and you crack the other side apart -- sort of like taking the shell off a pistachio nut.

You never PULL them open. And you never PULL ON THE BEADED part of the jewelry to open them. Pulling can loosen the magnet in its setting; it can also result in breaking the stringing material the piece is strung on. For bracelets, then, opening and closing them is very difficult for one person alone, without the help of another.