Safely & Efficiently: The flame retardant shell provides safety and insulation when wiring, pre-twisting wire is no needed. Safely connect wires without soldering or electrical tape, no tools necessary. Cone shaped spring pull the wires into connector and screw on, spring insert ensure a stable connection when working on wiring projects. Five Color-Coded: Include five color-coded assortment of grey, blue, orange, yellow and red connectors, assorted size fits for most electrical wiring projects and applications, great addition to your electrical connector kit! Applications: The twist on electrical connectors are great for home theater, speaker wire, stere wiring, automotive, marine wiring projects, househould wiring projects, commercial or residential applications, etc. Assortment Gauge: 50pcs Gray , min 2x#22 max 2x#16, 50pcs Blue , min 2x#22 max 3x#16; 50pcs Orange min 1x#18 and 1x#20 max 4x#16 and 1x#20; 18pcs Yellow min 2x#18 max 4x#14 and 1x#18; 12pcs Red min 2x#14 max 2x#10 and 2x#12, total come with 180pcs screw twist connector cap. Easy to Sotrage: Our screw-on wire connector assortment packed into a divided storage box to keep the different wire connectors separately. Covenient to storage and use.