Great checked shirt from Polo Ralph Lauren, made in their Lowell Sport Fit in a light and soft two-ply cotton

Chest Width: 65
Front Length: 81

Hot tip for buying vintage online
Please be aware that sizes and fits vary greatly from brand to brand, and decade to decade. Instead of just following the garments' S/M/L labels, we recommend comparing the garments' measurements with a similar product you own and know fits you.