the OMM Core Arm Warmers

the OMM Core Arm Warmers

See our entire range from the OMM here!

The OMM Core Arm Warmers are ultra-lightweight and breathable arm warmers for running, cycling, hiking and other activities where temperatures can change quickly. They provide extra warmth over your arms without having to stop and put on a full mid-layer.

The arm warmers weigh only about 35 grams per pair and take up very little space in your running vest or backpack. Pull them on when the wind picks up, the temperature drops or you reach an exposed mountain ridge – and tuck them away again when it gets warmer.

PrimaLoft® ACTIVE 75 g/m²

The open PrimaLoft® ACTIVE material combines synthetic insulation fibers with a thin knitted mesh. The construction creates insulating air pockets while maintaining very high air permeability.

The material wicks away moisture, dries quickly and continues to provide insulation when damp, making the arm warmers particularly useful during intense activities and in changing weather.

Adaptive warmth during activity

Core Arm Warmers provide breathable insulation but have very limited wind protection. When worn alone, air can pass through the material and release excess heat. Under a windbreaker or shell jacket, more warm air is trapped and the insulation becomes more effective.

This design makes it easy to regulate your temperature without extensive clothing changes. The arm warmers work especially well with a short-sleeved running shirt and a light windbreaker.

Stretchy and body-hugging fit

Four-way stretch and OMM Performance Fit provide a flexible fit that keeps the arm warmers in place as you move. Flatlock seams lie flat against the skin and reduce unnecessary bulk under an outer garment.

The model is available in combined sizes S/M and L/XL. The arm warmers should fit relatively close to the body without restricting freedom of movement.

Benefits

Ultralight arm warmers for intense activity

Weighs only about 35 grams per pair

PrimaLoft® ACTIVE 75 g/m²

Breathable synthetic insulation

Quick-drying material

Insulates even when damp

Four-way stretch for good freedom of movement

Body-hugging Performance Fit

Flatlock seams

Very small packing volume

Easy to put on and take off during activity

58% recycled material

Works effectively under a windbreaker or shell jacket

Specifications

Product type: Insulating arm warmers

Area of use: Trail running, mountain running, cycling, fastpacking and hiking

Material: PrimaLoft® ACTIVE

Material weight: 75 g/m²

Weight: Approximately 35 g per pair

Stretch: Four-way stretch

Fit: Performance Fit

Seams: Flatlock seams

Sizes: S/M and L/XL

Color: Black

Recycled content: 58%

Care instructions

Always follow the washing instructions on the product label. Wash the arm warmers gently with similar colors and avoid fabric softener, as this can impair the moisture-wicking properties of the material. Allow them to air dry and avoid direct contact with Velcro or other details that can damage the open material structure.

The OMM Core Arm Warmers are lightweight and stretchy arm warmers made from PrimaLoft® ACTIVE. The model features four-way stretch and a body-hugging Performance Fit that keeps the arm warmers in place without restricting freedom of movement.

The arm warmers are available in two combined sizes: S/M and L/XL . OMM does not publish separate measurements for arm circumference or sleeve length for the model. Your usual size in OMM tops is therefore the best starting point.

Size guide

The sizes may be shown as Small and Large in some product menus. Small corresponds to S/M and Large corresponds to L/XL.

How to choose size

Choose S/M first if you normally wear size S or M in OMM tops. If you usually wear L or XL , L/XL is the natural starting point.

The size is mainly influenced by:

• upper arm circumference
• arm's length
• How close to the body you want the arm warmers to fit
• whether they are to be used directly against the skin or on top of a thin garment
• how much the arms change in circumference when the muscles work

If you have narrow arms in relation to your upper body size, the smaller size may provide better stability. If you have thicker upper arms or long arms, the larger size may provide better comfort and coverage.

How to measure your arm

OMM does not provide exact measurements to compare with, but you can use your own measurements when assessing the fit:

1. Let your arm hang relaxed at your side.
2. Measure around the widest part of your upper arm without tensing the muscles.
3. Measure both arms and start from the larger one.
4. Also measure the length from the point where the arm warmer should start on the upper arm to the wrist.
5. Feel free to compare with a pair of arm warmers that already fit well.

Do not pull the measuring tape too tight. The arm warmer should be close to the skin, but the size should not be based on the material having to stretch to the maximum.

How should Core Arm Warmers fit?

Core Arm Warmers have a body-hugging performance fit. The material should follow the arm and lie relatively flat to provide effective insulation and reduce the risk of the arm warmer slipping while running.

The right fit means that:

• the top edge remains in place when the arms move
• the material lies close to the skin without being tight
• you can bend and extend your elbow freely
• the seams do not rub in the armhole
• the material does not form large folds around the elbow
• the wrist can move freely
• blood circulation is not restricted
• The arm warmer overlaps the shirt sleeve without leaving a gap.

A little material wrinkling at a bent elbow is normal. However, heavy wrinkling or material gathering and sliding indicates that the size may be too large.

If you are between S/M and L/XL

Choose S/M if you prefer a close fit and it doesn't tighten around the upper arm. It is often the better option if you usually wear size M but have relatively narrow arms.

Choose L/XL if:

• S/M leaves clear pressure marks
• The top edge feels tight
• the material tightens when the elbow is bent
• the sleeve length does not provide sufficient coverage
• you have strong upper arms
• you want to wear the arm warmers on top of a thin base layer

Don't choose the smaller size just to prevent the arm warmers from slipping. If the top edge has to fit very tightly, both comfort and circulation can be impaired.

Try the arm warmers in motion

The fit should be checked during movements similar to running:

1. Pull the arm warmer up to the desired position on the upper arm.
2. Make sure it overlaps the short sleeve of the shirt.
3. Bend and straighten your elbow several times.
4. Move your arms forward and backward as if running.
5. Raise your arms above your head.
6. Check if the top edge starts to slip.
7. Feel if the material is tight in the crease of the arm or at the wrist.

Feel free to leave the arm warmers on for a few minutes. Pressure that initially feels insignificant can become bothersome during a longer workout or race.

Directly against the skin or on top of a base layer?

Core Arm Warmers are primarily designed to be worn close to the body with a short-sleeved shirt. The PrimaLoft® ACTIVE material is soft, stretchy and quick-drying.

If the arm warmers are worn over a thin long-sleeved garment, you need to check that:

• both layers lie flat
• the material does not crease in the armhole
• the upper arm does not feel compressed
• the entire combination can move without resistance

The larger size may be more suitable over an extra layer, but the arm warmer should not be so loose that it slips.

The difference between the right size and too big a size

A roomy toe box or loose jacket can sometimes be intentional, but arm warmers need to sit relatively close to the arm to work well during activity.

Signs that the size is too large:

• The arm warmer slides down while running.
• the upper edge leaves a gap against the skin
• the material gathers around the elbow
• the wrist feels loose
• The arm warmer twists on the arm
• a gap occurs between the shirt sleeve and the arm warmer

Signs that the size is too small:

• the upper edge cuts into the upper arm
• you get clear print marks
• the material tightens when the arm is bent
• the seam pulls at the armhole
• your hand or forearm starts to feel cold or numb
• the arm warmer does not provide sufficient length

Important information about windbreaks and storage

PrimaLoft® ACTIVE is highly breathable. The arm warmers provide insulation and wick away moisture, but are not a windproof or waterproof shell.

In strong winds, they provide the best warmth when worn under a protective jacket. The body-hugging fit makes it possible to add a shell without unnecessary bulk around the arms.

Check the correct model

The OMM Core Arm Warmers have the article number OC211 and are available in sizes S/M and L/XL. This model should not be confused with the OMM Swift Arm Warmers, which have a different material construction and fit.