Unsurpassed quality and durability in a high-leverage easy-on wing-type design wings are knurled for a sure grip and offset from centerline for greater twisting leverage square-wire plated spring instantly adjusts to the shape and size of the splice flame-retardant properties resist heat distortion up to 105 c 221 F high-dielectric shell features deep skirt design to prevent exposure of bare wire copper-to-copper connections only connection rated at 600 v Max. For building Wiring and rated at 1 000 v Max. In lighting fixtures/luminaries and signs. Unsurpassed quality and durability in a high-leverage easy-on wing-type design.