The Pacific Denim Shirt in Light Wash Denim from Knickerbocker, NYC. 

Details
The Pacific Denim Shirt Draws Inspiration From Classic American Workwear. It's Built To Last With Felled-Seam Construction And Bartacks At Stress Points. Made From Lightweight Japanese Denim With Rope-Dyed Yarn That Will Age Beautifully Over Time. For A Blend Of Traditional And Modern Style, They Chose Clean Natural Shell Buttons Instead Of Melamine Or Metal. 

• 100% cotton, woven in Japan. 
• Shell buttons.
• Made in Portugal.