Other promotional gear just doesn't measure up to this cool keychain that does double duty! This 1.58" x 3.15" x 0.6" aluminum carabiner-style keychain with has a bright light and printed 2" ruler. The light features Chip on Board technology and three settings -- steady on, dim and blinking. Each comes with two installed and replaceable CR2032 button cell batteries and put out between 40 to 50 lumens. Choose from black or blue and add your school, sports team, organizational or company logo, emblem or message to create a bold branded gift or giveaway for marketing and social events and activities.