Merino wool is finely crimped and soft. Staples are commonly 65–100 mm (2.6–3.9 in) long. Merino wool is generally less than 24 micron (µm) in diameter. Basic Merino types include: strong (broad) wool 23–24.5 µm, medium wool is 19.6–22.9 µm, fine 18.6–19.5 µm, superfine 15–18.5 µm and ultra fine 11.5–15 µm. Ultra fine wool is suitable for blending with other fibers such as silk and cashmere. New Zealand produces lightweight knits made from Merino wool and possum fur. Merino is excellent at regulating body temperature, especially when worn against the skin. The wool provides some warmth, without overheating the wearer. It draws moisture (sweat) away from the skin, a phenomenon known as wicking. The fabric is slightly moisture repellent (keratin fibers are hydrophobic at one end and hydrophilic at the other), allowing the user to avoid the feeling of wetness. Like cotton, wool absorbs water (up to 1/3 its weight), but, unlike cotton, wool retains warmth when wet, thus helping wearers avoid hypothermia after sweating from strenuous exercise or getting rained on when outside. Like most wools, merino contains lanolin, which has antibacterial properties. Merino is one of the softest types of wool available, due to finer fibers and smaller scales. Merino has an excellent warmth-to-weight ratio compared to other wools, in part because the smaller fibers have microscopic cortices of dead air, trapping body heat similar to the way a sleeping bag warms its occupant.