The most flexible and powerful pace and game clock ever made. Integrated Bluetooth® connects to Android or iPhone smart phone with Swim Clock app. Super bright 6.5 inch red LED display is easily visible indoors or out. Optional internal, rechargeable 12VAC battery has intelligent charging circuit so you can't over-charge. 10+ hours of continuous operation per charge. All parts and labor covered by 5 year warranty (except batteries—2 years). Has a rugged Aluminum case with a Plexiglass lens.