The Caltrop is designed to take the wind out of the equation when you walk up to that tough putt. Overstable enough to prevent too much air play and featuring a raised thumb grip, the Caltrop will help make even the windiest courses seem calm! Opto is a max-durability grippy and translucent plastic that is great for putter upshots and drives. Features: Stability Rating: 0 Opto Plastic