4Core SM Ultra Light, 200m on drum *** SM= Single Mode 9/125 Fiber Core (Yellow Rings on Connector) Ultra Light cable is a strong, flexible cable with a diameter of only 4.8 mm., very useful in controlled environments like studios and film sets. Ultra Light cable is bringing you smaller drum sizes and less weight. Specsfour cores of protected fibersingle mode 9/125outer cable diameter 4.8 mm.color coded (four yellow rings for 4Core single mode)cable length 200 meters in totalrobust male cable connector on both sideswound on Schill GT310 drum