Safely and effectively: Flame retardant shell provides safety and insulation when wiring, pre-twist wire is not required. Securely connect wires without soldering or electrical tape, no tools required. Cone-shaped spring pulls wires into connector and screws into place, spring-loaded insert ensures a stable connection when working on wiring projects. Five color codes: includes an assortment of five gray, blue, orange, yellow and red colored connectors, assorted sizes for most electrical wiring projects and applications, a great addition to your electrical connector kit! Applications: Twist-on electrical connectors are perfect for home theater, speaker wire, stereo wiring, automotive, marine wiring projects, household wiring projects, commercial or residential applications, etc. Assortment Gauge: 50pcs Gray Wire Nuts, min 2x #22 max 2x #16, 50pcs Blue Wire Nuts, min 2x #22 max 3x #16; 50pcs Orange Wire Nuts min 1x #18 and 1x #20 max 4x #16 and 1x #20; 18pcs Yellow Wire Nuts min 2x #18 max 4x #14 and 1x #18; 12pcs Red Wire Nuts min 2x #14 max 2x #10 and 2x #12, total comes with 180pcs screw cap. Ease of Storage: Our screw on wire connector assortment is packed in a divided storage box to keep the different wire connectors separate. Suitable for storage and use.