Woodhead 5622WBLK Cable Strain Relief Grip, Locknut, Max-Loc Cord Seal, Straight Male Single Hole, 3/4" NPT Thread Size, Gray Grommet Color, .250-.375" Cable Diameter Gray nylon body is resistant to impact and corrosion Black nylon body is resistant to impact, corrosion and uv/sunlight Rubber grommet provides a liquid-tight seal and reduces cord pull-out Grommets are color-coded for easy identification Rubber grommet is best material to resist chemicals and handles a wide temperature range