M23 Elite Threaded and Checkmate™ Connectors Amphenol Sine Systems M23 Elite Threaded and Checkmate™ Connectors are designed with expanded connector options and are compatible with other industry-standard products. The connectors feature a next-generation single PC design, loose-PC insert assembly, ground protection, top-loading design, Checkmate coupling, and 360° shielding. Amphenol M23 elite connectors are available in 6, 8, 9, 12, 16, and 17 positions. These connectors do not require any extraction tools for power inserts.