To sell a vintage **BIG MAC** flannel shirt for a high price on Mercari, the key is to emphasize "hints of specific era" and "good condition" to attract fans. Judging from the photos, the tag design (white background with red letters, 100% COTTON) suggests a rare piece from the late 1970s to early 1980s. Below is a high-rating, high-value sales description that you can copy and paste directly. Example Title: [Rare & Great Color Combination] 70s-80s BIG MAC Big Mac Flannel Shirt M Green x Gray x Yellow Vintage 100% Cotton Single Color Tag Thank you for viewing. Product Description [Brand] BIG MAC / Big Mac (J.C.Penney) [Era] Late 1970s - Early 1980s [Item Details] This is a classic and iconic vintage garment, a heavy flannel shirt from BIG MAC. Made of thick 100% cotton flannel fabric, which has seen its price rise in the vintage market in recent years. This piece has an outstanding feel, with the soft texture and unique character of well-worn cotton that cannot be replicated in current products. [Points] • Color Combination: A very rare and attractive color combination based on calm green and gray, with yellow lines that work perfectly with any denim or chinos. • Details: No flap pockets on both chests, dish buttons, and a white tag that retains the texture of the time. • Size: Rare "M" size. Many vintage flannel shirts are too large, but this is a golden size that fits the Japanese physique. [Condition] As a vintage item, there is some overall wear and pilling, but there are no noticeable stains, holes in the cuffs, or missing buttons. The fabric is also sturdy, and it is in very good condition for a flannel shirt of this era. [Actual Measurements] • Shoulder Width: Approximately 45cm • Body Width: Approximately 54cm • Length: Approximately 70cm • Sleeve Length: Approximately 59cm Color: Green系 Pattern: Check Stains, Tears, Odors, etc.: Yes