While aluminium construction is still often seen for touring and recreational skiing, race oriented cross country ski poles are almost exclusively made with composites. Value priced models often used by high schoolers and team skiers are usually a mix between carbon fiber and fiberglass. More expensive models add progressively higher amounts of carbon with the most expensive models featuring high grade epoxies and custom weaves or braids of carbon.
As with the skis themselves, ski poles differ in length depending on whether you are classic skiing or skating. Specifically, classic poles tend to be 7 to 10 centimeters shorter than skate poles to account for the striding motion within classic. Unlike skis, however, poles ARE fit by height. The general rule is that classic poles should come to the top of the skier's shoulder, while poles for skating should come between the skier's lips and nose.