1952 US Mint Proof Set *Plastic Case* Proof
Sales Rank in Collectible Coins: 316 (previously unranked)
(Visit the Movers & Shakers in Collectible Coins list for authoritative information on this product's current rank.)
source https://www.lifetechnology.com/blogs/life-technology-holistic-health-products-blog/9-1952-us-mint-proof-set-plastic-case-proof