1. Case: stainless steel 2. Fill fluid: Glycerin 3. Dial: Alu. 4. Connections: 1/8" NPT,1/4"NPT 5. Pressure range: 0-1000psi PRODUCT SPECIFICATIONS Sizes:2 1/2", 4"Case:304 stainless steelFill Fluid:GlycerinWindowPolycarbonateDialAluminumPointerAluminumBourdon Tube:BronzeConnections:1/8"NPT, 1/4"NPTPressure Ranges:0-1000psiAccuracy:±3%; ±2%; 3%