Sierraplex ribbed bakelite ivory wall receptacle plates. Markings show The Sierra Line McDonald Mfg Co. Los Angeles, California. Made in USA D-1R Patent Applied For. Center opening measures 2 15/16 inches by 1 1/16 inches (74mm by 27mm). Salvaged from a home built in the 1950s. Shipping for multiple items add $1 for each additional cover plate.