MPO / MTP connectors are mostly used in high value, high reliability environments. Although MPO-12 is the most common connector today, datacenters are migrating to MPO-24, and MPO 16 / 32 are coming. Typically found in (multimode) 40, 100, and 400Gbit Ethernet installations, but also in single mode & custom data systems - either service provider or based on MSAs. Systems usually have breakout cables with other connectors, such as LC or SC. Extremely accurate optical loss test accuracy is required, as allowable cable losses are very small. Major irritations are a combination of high fiber counts, unforgiving test accuracy requirements, and overly expensive test equipment.