The GP5 BioKork offers all the ergonomic advantages of the GP5, but combined with unique BioKork technology.385g per pairWhy BioKork?The unique qualities of cork means that it is antibacterial and hypoallergenic. Cork's natural damping qualities also make it an ideal grip material, and its low density mean the resulting grip is a lot lighter. The bioKork grips use 40% cork, sourced from sustainable forests in Portugal which is certified for its ecologically sound production. This ecological theme is continued throughout the rest of the grip. The inner core is plastic reinforced using natural fibre, which make up 40% of its mass. in place of mineral oil, the gel in the palm section of the grip is vegetable oil based. it is all a result of Ergon's ÔÇ£GreenLabÔÇØ initiative.