FieldCast 2Core SM Heavy Duty Cable (200m on Drum) 2Core SM Heavy Duty, 200m on Drum *** SM= Single mode 9/125 Fiber Core (Yellow Rings on Connector) Heavy Duty cable is a very strong and robust cable with a diameter of 6.5 mm. Use it in the field, or wherever you need the most reliable fiber optic cable connectivity at any distance. Specs two cores of protected fiber single mode 9/125 outer cable diameter 6.5 mm. color coded (two yellow rings for 2Core single mode) cable length 200 meters in total robust male cable connector on both sides wound on Schill GT380 drum product code: c1200