USW 12/3 Twist to Lock Multi Outlet Adapter 3-ft 12 / 3-Prong Indoor/Outdoor Sjtw Heavy Duty General Extension Cord in the Extension Cords department at Lowes.com
100ft. 12/3 TriTap Extension Cord with Lighted End Plug
GENERAL ELECTRIC 3-Outlet Grounded Extension Cord, Braided, 1 Feet, Indoor, Gray/White - Walmart.com
Iron Forge Cable 15ft Outdoor Power Extension Cord with 3 Outlet, 16/3 Weatherproof 15 ft Green Extension Cord with Multiple Outlets 3 Prong, Great for Christmas Lights and Outside - Amazon.com