The CTJ-3A-10-4021 is a metallic feedback frame rail from the DEUTSCH CTJ3 series, designed to hold common termination system modules. Constructed from lightweight extruded aluminum alloy with stainless steel clips, it features a durable black anodized finish. This rail has a capacity for 10 modules (for sizes 22, 20, or 16) and a length of 5.180 inches, with elongated mounting holes for easy installation. A special modification marks the module locations with sequential numbers instead of the standard alphabetical identification. It provides a versatile and rugged mounting solution for wire termination systems in aerospace, defense, and marine applications.