MOST IMPORTANT FACT, THIS IS AN ORIGINAL SUNDING BIKE COMPUTER,with so many counterfeits around you can relax about this speedometer, it was purchased direct from the factory.

Digital Bike Bicycle Speedometer Cycle Odometer Computer MPH KMH waterproof LCD With Battery Included 

Bike Speed meter 
Model: SD-548B
Size: 4.4cm x 4.7cm x 2cm / 1.7 x 1.9 x 0.8 inch
Weight: 23g(Computer Console)
Display Screen: LCD
Sensor Cable Length (Approx.): 85 cm / 33.5 inch
Package Included: cycle computer + mounting shoe + sensor cable + magnet + sensor transmitter + cable ties + LR44 battery

Functions:
1. SPD : Current Speed ;up to 99.9 km/m (m/h)
2. ODO : Odometer (0.001 ~ 99999 km/m)
3. DST : Trip Distance (range from 0 ~ 9999 km/m)
4. MXS : Maximum Speed
5. AVS : Average Speed
6. TM : Elapsed Time (0:00:00 ~ 9:59:59)
7. CLK : Clock (12H/24H)
8. Speed comparator ("+" "-")
9. Scan : Screen display varies among DST, MXS, AVS, and TM every 4 seconds
10. Setting Speed Scale (km/h, m/h)
11. Setting Tire Circumference (0 ~ 9999mm)
12. Setting the last value of odometer/ODD (km/m)
13. Maintenance Alert
14. Freeze Frame M