Aluminum tank, powdercoated black to prevent corrosion in a water cooling system, preinstalled with a MaxiJet 1000, 265gph Powerhead Pump. Fittings are now in chrome, with 1/2" option! Reservoir has a fill port included. Measures 4.5" x 4.5" x 2.4". Hose barb (to the right on photo) can be replaced with an elbow (1/4NPT to 3/8" barb, available seperately below) for easy hookup to a radiator. Maxi-jet powerheads are extremely reliable - In the aquarium industry, these have a MTBF (mean time between failure) of over 10 years! 2-3 times more flow rate than the smaller minijet reservoir.