Mountain bike speedometer with blue luminous

product description】 ★ 28 major functions ★ Blue luminous ★ Shundong SD-558A code table 【Model】 SD-558A 【Material】 Engineering plastics, LCD display, electronic components, etc. 【Display】 Double row and four window display (pictured) [Size] Product size 9 * 4.5 * 1.5CM; display size 7.3 * 1.7CM; line length is about 82CM [Power] 1 CR2032 button battery (inclusive) 【Packing】 Color box elevator [Annex] A copy of the original Chinese manual 【The main function】 ● Dynamic display of mileage, riding time, real-time speed, travel time, current time, current date; ● Query speed, average speed, total driving time, total mileage, current temperature at any time; ● With luminous function, using high-brightness cold light source, you can check the information at night at a glance (17: 00-8: 00 in the morning, press any key to turn on the backlight, it will automatically extinguish after about 4 seconds. bright); ● With metric / imperial unit s