When sourcing an acoustic plaster system, the most critical metric is the Noise Reduction Coefficient (NRC), which should typically range between 0.80 and 1.0 for high-performance environments. Buyers must verify the system thickness (usually 25mm to 40mm) as it directly impacts low-frequency absorption. Additionally, ensure the material has a Class A Fire Rating (ASTM E84 or EN 13501-1) to meet international building safety codes. For seamless aesthetics, confirm the Light Reflectance Value (LRV) is above 80% to optimize indoor lighting efficiency.