Yes it is compatible. Item # MET-W48V 48 Volt Battery Status, Power On, and Headlight On Indicator is compatible with item # SPD-481000B speed controller.
The MET-W48V indicators red wire connects to the SPD-481000B controllers red power light connector wire. The MET-W48V indicators black wire connects to the SPD-481000B controllers black power light connector wire. The MET-W48V indicators white wire connects to the scooters positive headlight wire. If the scooter does not have a headlight then the white wire does not have to be connected to used. The indicator will still function with the white wire disconnected.
Please let me know if you have any further questions.
thanks :P best support site ever
so i want to have a speed indicator so i thought i buy this one 48 Volt Battery Status, Power On, and Headlight On Indicator is it competible with this speed controller ? http://www.electricscooterparts.com/hookup/SPD-481000Bwiring.htm