the OMM Core Tee

the OMM Core Tee

See our entire range from the OMM here!

The OMM Core Tee is an ultralight, short-sleeved insulated top for trail running, ultra running, fastpacking and intense mountain adventures. Made from the lightest version of PrimaLoft® ACTIVE, the top provides warmth with minimal weight and pack volume.

The open construction effectively releases excess heat when worn alone. Instead, when worn under a windbreaker or shell jacket, warm air is trapped, making the Core Tee a flexible reinforcement garment for activities where intensity and weather can change quickly.

PrimaLoft® ACTIVE 75 g/m²

PrimaLoft® ACTIVE is made from synthetic insulation fibers woven into a fine polyester mesh. The construction creates insulating air pockets without the extra layers of fabric typically used in lined garments.

The result is a very lightweight and compressible garment that continues to insulate even when the material gets damp. The Core Tee can be worn directly against the skin, over a thin base layer or as an insulating mid-layer under a windbreaker or shell jacket.

Customizable insulation for high activity

The airy material has very high air permeability. When used as an outer layer, the Core Tee allows wind and air movement to quickly transport excess heat away, reducing the risk of overheating during steep climbs and intense runs.

When the shirt is covered with a windproof outer layer, more warm air is trapped inside and the insulation effect is increased. The temperature can therefore be regulated by opening, removing or putting on the outer layer without having to pack the Core Tee away.

The Core Tee, however, provides very limited wind protection on its own. In cold or windy weather, it works best with a windbreaker or shell jacket.

Short-sleeved design and small pack volume

The short-sleeved construction provides extra insulation over the torso while the arms have good freedom of movement and ventilation. The very low weight makes the shirt easy to carry as a spare reinforcement in your running vest or backpack.

Flatlock seams are positioned away from the shoulders to reduce bulk and friction when wearing a running vest or backpack, and the softly rolled collar provides a comfortable finish around the neck.

Benefits

Ultralight, short-sleeved insulation shirt

PrimaLoft® ACTIVE 75 g/m²

Weighs approximately 75 grams in size M

Very high air permeability

Effective ventilation during high activity

Continues to insulate when the material is damp

Very small packing volume

Can be worn directly against the skin or over a base layer

Effective as a mid-layer under a windbreaker or shell jacket

Flatlock seams positioned away from the shoulders

Softly rolled collar

Reflective logo

Materials with 58% post-consumer recycled content

Suitable for trail running, ultra running, fastpacking and hiking

Fit and size

The OMM Core Tee has a close-fitting fit. It is designed to be worn directly against the skin or over a thin first layer without unnecessary bulk.

Typically, choose your regular size for a technical fit. If you are between sizes or want to wear the jersey over a heavier base layer, the larger size may provide more room.

Specifications

Type: Short-sleeved active insulation shirt

Area of use: Trail running, ultra running, fastpacking and hiking

Material: PrimaLoft® ACTIVE

Material weight: 75 g/m²

Weight: Approximately 75 g in size M

Fit: Fitted

Seams: Flatlock seams placed away from the shoulders

Details: Softly rolled collar and reflective logo

Recycled content: 58% post-consumer recycled material

Material standards: bluesign® and OEKO-TEX® approved

Care instructions

Always follow the washing instructions on the garment label. Turn the sweater inside out before washing and avoid washing it with garments or equipment that have Velcro fasteners, as these can damage the open PrimaLoft® ACTIVE material.

The OMM Core Tee is a lightweight, insulating, body-hugging garment. It can be worn directly against the skin or over a thin first layer and is designed to provide warmth without unnecessary bulk.

Size chart

The measurements refer to the body, not the garment itself. Use the chest measurement as a primary guide and use the body length and waist measurement as additional guidance.

How is the OMM Core Tee sized?

The Core Tee has a close-fitting, athletic fit . The model should sit relatively close to the body to function effectively as a first layer or thin insulation, but it is not intended to fit as a compression garment.

Compared to many common outdoor and leisure shirts, the Core Tee can feel small and narrow. The stretch material provides some adjustment, but the garment should not be tight across the chest, armpits or shoulders.

Fit example

Published fit examples show the following:

• A person who is 172 cm tall and weighs 62 kg experiences S as tight and M as a normal fit.
• A person who is 175 cm tall and weighs 60 kg uses size M.
• An external retailer recommends considering a larger size as the model may feel smaller than the equivalent size from other brands.

The examples are indicative. Body shape and desired number of layers will affect which size fits best.

Our size recommendation

Normally choose size according to your chest circumference:

• Choose the size that corresponds to your chest measurement for the intended body-hugging fit.
• If you are between two sizes, we recommend the larger one.
• Choose the larger size if the Core Tee is to be worn over a base layer.
• Choose the smaller size only if you want a very close fit and all body measurements are within the size range.
• If you usually need extra space over your shoulders, chest or stomach, you should go up one size.

How do you measure?

Chest circumference

Measure around the widest part of your chest. Keep the tape measure horizontal and close to your body without pulling it too tight. Your arms should hang loosely at your sides.

Waist

Measure around the narrowest part of your torso or where the shirt normally sits against your body. Keep the measuring tape loose.

Body length

Measure your height without shoes. Body length is primarily a guide to garment length – chest circumference should guide size selection.

Check the fit

Core Tee fits correctly when:

• the garment follows the body without large folds,
• the material is not tight across the chest or shoulders,
• the sleeves do not cut into the underarms,
• you can lift and stretch your arms without hindrance,
• the bottom edge stays in place during movement,
• There is room for planned layers over or under the shirt.