Blackheart Crossbow String Black. Result: crossbow strings featuring our innovative GlideLock servings and exclusive DuraWeave construction that makes for the absolute finest system available today. Each string is meticulously crafted to fit your crossbow. Specifications for Blackheart Crossbow String 81289: Manufacturer: Blackheart Color: Black Features of Blackheart Crossbow String: GlideLock serving DuraWeave construction 34.375" inch string Package Contents: Blackheart Crossbow String Blackheart 81289: Crossbow String 81289 Black