Cobra ladies golf bio cell ironsbio cell irons are packed with game changing technologythe long and mid irons feature heavy tungsten weights strategically positioned in the heel and toe for more forgiveness and the short irons have the tungsten positioned directly behind the hitting area for a solid feel optimal spin control and versatility as you approach the green the irons also feature cobrarsquos largest unsupported face ever to create more face flex at impact for increased ball speed