Lighting Control Adapter gmc es 5in W x 12 5in W x 12 FEATURES:Distribution & Return System Features:High efficiency systemLargest self contained PVC return gutter on the market todaySubmersible pumps Pad Features:Water is spread evenly over the pad surface as a film rather than droplets for uniform wettingPad surface dries quickly in absence of water to inhibit micro organism growthCoated pads are tough and durable for repeated cleaning Lighting Control Adapter D (LMA 12) is specially designed for controlling D ballast This Lighting Control Adapter S (LMA 13) is specially designed for controlling Sun System ballast