aluminum, strong and stable handle. The holder is infinitely adjustable... Reef Factory Reef Flare Pro Arm M/L - Black Reef Flare Pro arm is a kit to mount Reef Flare lamps size S, M and L directly on an arm on the edge of the aquarium. Made of aluminum, strong and stable handle. The holder is infinitely adjustable in both axes. Most important features Mounting the Reef Flare Arm directly into the tank Height and length adjustment possible Quick installation Dimensions Reef Flare Arm S: Length 450mm Handle width 40mm Height 290mm