Strauss Bicycle Speedometer, (Black/Red) and Mobile Holder (Black) This bicycle speedometer is waterproof and works great on rainy days as usual when riding Easy to install and use it is easy to follow instructions, great basic functions of the speedometer and very specific tire size that enable accurate calculations. Portable size, light weight, wide application this bike odometer is only for 1.8 x 1.8 inches (l x w) and 0.18 lb, which is easy to carry and save your space The full protection: Buckle structure phone cradle to lock your cell phone secure with soft non-slip and non-scratch protection pads Easy installation: Easy to install/remove, no any other tools required Wide handlebar compatibility: Bike/bicycle phone holder size is adjustable to fit tubular handlebar sizes up to 30mm(1.2inches)