Warm, unbulky, comfortable
Perfect for cold-cool morning commutes (~30-40F); warm, unbulky, unbinding, doesn't slip, long enough to cover wrists, but stretchy enough to easily move away from watch. Easily adjusts on biceps to allow a bit of pit-venting between short-sleeve shirt sleeve and top of arm warmer. Packs small, stays unstinky. Can't comment on durability yet. I have size small, my biceps max at ~11". It just fits in the forearms and biceps - if it stretches out I may have issues with slipping.

Great quality product!
I have not used the product, but looking at its construction, it looks well made and durable. I also have the Smartwool arm warmers and these Ibex arm warmers appear to better made overall, but they are also more expensive. The sizing are for men; for women, make sure you order a size lower than what your normal size would be.

Sold on wool
You can't beat the comfort of wool on cool winter days. These lightweight arm warmers are perfect for these conditions and fold neatly to fit in your back pocket when unneeded. The elastic bands keep the warmers in place without the annoyance of rolling down your arms.

Most
Whether I am biking or running the easiest way for me to moderate my temperature is through a good pair of arm warmers. They are up when I am chilled and pushed down when I need to cool off. The mid weight Merino wool of the Ibex arm warmers is soft and provides just the right amount of protection from wind and weather while retaining its warmth when it is wet. The encased elastic at the top opening keeps the arm warmers exactly where you want them and their stretchy fabric composition provides a comfortable fit without any circulation issues.(I've had this with other arm warmers that are too tight.) The 5 oz. arm warmers are small enough to fit into your back pocket when not being worn and cheap enough to not put a dent in your budget.