1st generation Jetson Bolt's have a black rear hub motor and a red trim on the tires. The 1st generation Bolt is not Bluetooth enabled.
2nd generation Bolt's have a black rear hub motor and a green trim on the tires. The 2nd generation Bolt is Bluetooth enabled.
3rd generation Bolt's have a orange colored rear hub motor and orange accents on the seat and bike stem. The 3rd generation Bolt is Bluetooth enabled.
4th generation Bolt's have a red rear hub motor. The 3rd generation Bolt has a bell instead of a horn. The unit is Bluetooth enabled.