These fully jacketed light strings are UL® listed and meet OSHA requirement #1926.401(j)(l). Sockets are rated 150 watts and spaced on 10 foot centers. Features an open metal bulb guard for easy bulb replacement. Molded-on weather and heat resistant lamp sockets and plugs. Heavy duty 12/3 all vinyl cord is weather resistant for outdoor use. “STW-A” is an extra hard service cord, 600 volt, with a thermoplastic constructed jacket. (Suitable for outdoor use.) Ready to use.