Xiaomi scooter pro 2 vs 4 pro July 8, 2019 16 32 64 128 Xiaomi mi electric scooter pro 2 vs 4 pro Xiaomi scooter 4 pro vs 4 pro gen 2 Xiaomi electric scooter 4 pro vs 4 pro gen 2 Xiaomi scooter pro 2 vs 1s