Sock poi make a great starter pair of poi because they are so simple and impossible to tangle.  They feel great in your hands since they are made of a fabric like that of t-shirts which is kinda stretchy and silky yet, very durable and responds comfortably to your every spinning move.  Inside the sock is a tennis ball and, at the handle area there is a 1 inch diameter ball you will place between your fingers when you grip your sock poi.  They are about 20 inches from tip to tip.