This item is designed to either couple or split an optical signal. Use this device to combine two accessories such as DVD, DAT, or Digital headphone into a piece of equipment with only one input. You may also use the device to split your digital signal and direct it to two similar devices. There are two (2) POF (plastic optical fiber) receptacles on one (1) end and one receptacle on the other end. Dimensions: 2 1/4 L x 1 1/2 W x 3/4 D.