Iron Heart 14oz Indigo Dyed Ultra-Heavy Buffalo Check Flannel Workshirt

Size Guide
Back again! Here we have some of the best flannels!

For the first time ever, Iron Heart has brought us an indigo thread-dyed version of their classic Ultra-Heavy Flannel!

A timeless style you can wear for a lifetime. No better feeling than seeing your fave flannel become better with time, and now you can enjoy the beauty of indigo ageing along with it!

Famous for their heavyweight garments, Iron Heart's flannel fabric is slowly woven with vintage machines using Peruvian Aspero cotton to create a garment that is super-comfortable yet durable!

The pattern is sharp and textured, unlike brands that use cheaper printing methods. With time the thread-dyed indigo fabric will reveal many variations of beautiful indigo hues!

For durability, this one is skillfully constructed using vintage machines and features classic workshirt styled chest pockets with a pencil slot. Chain stitch run-off make-up for a real worker vibe and the black urea buttons add some tasteful contrast in the natural light.

Gear up for your daily tasks.

  • 100% Cotton
  • Japanese 14oz ultra heavy flannel
  • Indigo is thread-dyed
  • Twin chest pockets
  • Urea buttons
  • Brushed interior
  • Once washed (minimal shrinkage)
  • Slim fit
  • Made In Japan

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How We Measure

Pants and Shorts


With the major buttoned up open the jeans and lay them flat like shown. Measure from the front where the major button closes to the back belt loop. Then double this measurement to achieve the waist measurement.

The way we measure is different from 'Side to Side', If you are not used to our method you should downsize by 1 inch.

For example, side to side measurement for The Flat Head 3002 waist is 28inch and using our method 29.25 inch.

Front Rise:

With the jeans lying flat measure from the crotch bar tack to the top of the waistband. 

Back Rise:

Spread out the crotch so the bar tack is visible, then measure from the crotch to the top of the waistband.


One inch down from the crotch measure flat across to the other side.


Flatten the leg and measure along the inseam from the crotch to the leg hem. 

Leg Openning:

Measure straight across the hem from side to side.



Lay flat then measure from the shoulder's edge to the other shoulder's edge.


Lay shirt flat and measure from pit to pit.

Sleeve length:

With the sleeve flat measure from the shoulder to the cuff.

Arm hole openning:

Measure from the shoulder down to the pitt.

Vertical length:

With the shirt facing down, Measure from below the collar to the bottom hem.