Iron Heart's Extra Heavy Cotton Knit Thermal Sweater in Black is a hefty thermal made for cool and brisk Fall/Winter days. These are a beefier version compared to the IHTL-1301, with the fabric being a bit more sturdier as well as thicker. These work well as a base layer with a slim fit.

Note: These run small, recommend taking one size up from your typical American tops size (or the same size as you would in your Iron Heart IHSH flannels) for a slim but comfortable fit. You can also take your typical tops size if you prefer to wear this as a base underlayer. The fabric will generally stretch a little in areas of tension. However, these do have less stretch/give to them than the , so we recommend not counting on as much stretch as the IHTL-1301. To compare measurements, keep in mind that these will generally hug closer to your body than a button-up shirt, so a smaller chest measurement in these thermals is probably preferred.

Model: 6'0'' and 175 lbs. wearing size L (his typical Iron Heart flannel size) for a comfortable and somewhat slim fit (not oversized). Model can also size down to M for a tighter fit and wear as a base underlayer, however the length becomes somewhat short. See model wearing size M in the . The fabric generally will stretch as needed in areas of tension, but does not stretch as much as the IHTL-1301.

• 100% extra heavy cotton waffle thermal knit
• Durable 4-needle flat seam construction
• Chainstitch run-off on sleeves and hem
• Ribbed collar and cuffs
• One-washed, expect minimal shrinkage
  
• Made in Japan