Switch hidden inside shoes, it nearby the USB port, you can press it to fix the shoe on one color, or flashing.
With a detailed size chart provided on this page, it should be easy to pick the best fit for you. For in-between feet sizes, we recommend a half-up size.
The LED shoes are special sneakers, they have the led light bars in the shoes sole, so please do not use them as running shoes.
Size chart: (Heel to Toe)
25 M EU / 9 M US-- (the foot length 6.10-6.33 inches or 155-161 mm)
26 M EU / 9.5 M US-- the foot length 6.34-6.57 inches or 161-167 mm
27 M EU / 10.5 M US--the foot length 6.57-6.85 inches or 167-174 mm
28 M EU / 11.5 M US--the foot length 6.86-7.12 inches or 175-181 mm
29 M EU / 12 M US--the foot length 7.13-7.36 inches or 181-187 mm
30 M EU / 13 M US---the foot length 7.37-7.63 inches or 188-194 mm
31 M EU / 1 M US----the foot length 7.64-7.87 inches or 194-200 mm
32 M EU / 1.5 M US----the foot length 7.88-8.14 inches or 201-207 mm
33 M EU / 2 M US-------the foot length 8.15-8.38 inches or 207-213 mm
34 M EU / 3 M US-------the foot length 8.39-8.70 inches or 214-221 mm
35 M EU / 4 M US????the foot length 8.71-8.97 inches or 222-228 mm

Osima Kids Boy and Girl's High Top Led Sneakers Light Up Flashing Shoes - B071YDKFYZ