ConeGrip - Forearm & Fingers Trainer New Conic Shape Thick Bar Adapter Grips Perfect for Body Building, Arm Wrestling, Weight Lifting, Climbing and CrossFit. Important note: The ConeGrip is made of High Quality Non-Slip rubber material, over time the Grip may become covered in white powder (Rubber Bloom). Rubber Bloom is a common, superficial phenomenon that does not affect the functionality of grip. Rubber Bloom is common and is not considered defective as it does not inhibit proper function of the rubber.