These three pictures show insulators that I recently got from the dismantling of the Point Du Bois transmission line in Winnipeg. This line was built in 1907-09. I thought the insulators on it were original, but some of them have markings indicating CP5. I think that must stand for Canadian Porcelain, but I thought they weren't in production until 1913 which is after this line was built. Does anyone have any idea how old these insulators are?