A toy lead is also known as a string lead and is meant for breeds under 6 pounds. The string lead thickness is 1/8" with a length of about 4'.  

This lead are used as an all-in-one-type lead with a neck loop, a bead to slide down to tighten around the neck, and a swivel so the lead will not twist up if the dog turns.  This type is detachable, and the lead has a small lobster claw clasp to attach to the neck piece easily.

This type come in a slip, kindness, martingale or martingale/kindness.