Features: Bike chain stabilizer can effectively prevent chain drop and chain jump. High-quality aluminum alloy, fine workmanship, durable and wear-resistant. Small in size and light in weight, it will not burden your riding. Suitable for single disc to make riding more stable and enhance your riding experience. Installation is simple and quick, suitable for mountain bikes, without disassembling the crank. Specifications: Model: Professional Type/ Simple Type(optional) Color: Black/ Red(optional) Material: Aluminum Alloy + Nylon Applicable: For standpipes with a diameter of 31.8-34.9mm Item Size: Professional: 80 * 60 * 25mm/ 3.1 * 2.4 * 1.0in Simple: 105 * 55 * 20mm/ 4.1 * 2.2 * 0.8in Item Weight: Professional: 43g/ 1.5oz Simple: 30g/ 1.1oz Package Size: 105 * 75 * 27mm/ 4.1 * 3.0 * 1.1in Package Weight: Professional: 87g/ 3.1oz Simple: 65g/ 2.3oz Packing List: 1 * Chain Stabilizer 2 * Wrench