This is a great tool for its price. This Bike Computer Odometer Speedometer has many useful functions. It is also very durable considering even you have put over 500 miles on it， you even don&acute;t have to change the battery. It is functioned as tracking your training progress in real time. Easy operation and durability make it popular with people. Generally speaking， with it， you can control your riding every moment.                                    Features            Easy to installGood quality， durableWhich wireless Bike built ball switch， sleep when the body shaking table， vibration sensors automatically turn the ball switchChronograph with waterproof function can be used in the rain， but not Qinru water useCode table on the back battery cover is open， being careful not to waterproof gasket lostTracking your training progress， valuable for training; Dual line LCD display                                                            Specifications            Material    Steel    <br>Color    Black    <br>Weight    111g/3.92oz    <br>Dimensions    9 x 5.5 x 4cm/3.54 x 2.17 x 1.57inch(L x W x H)    <br>                                                            Package Includes            1 x Mountain Bike Rear Derailleur Protector