The Ninja Hand Grip Black N6317 is a fitness accessory designed to enhance grip strength and forearm muscles. Typically crafted with durable materials, these hand grips are designed to provide resistance during squeezing exercises, helping users improve their hand strength and overall grip performance. The black color and model designation (N6317) may indicate a specific design or version within the Ninja Hand Grip product line. These grips are commonly used by athletes, climbers, and fitness enthusiasts to enhance hand and forearm strength for various activities.