General Questions & Answers:
If your fence has the t-posts spaced at 10 feet you will need 15 T-Post Toppers. One per T-Post.
There are three packaging options. 2x, 20x, 50x. So you would need one combo pack of 50, one combo pack of 20, and four combo packs of 2.
T-Post Topper is water resistant. There is no metal in its construction. T-Post Toppers will easily last as long as your fence stands.
Other topper units are metal. Causing it to be at the mercy of the weather. The T-Post Topper is made of polymer plastic allowing it to be strung with low volt powered electric wire.