Stack-Light.com offers a large selection of cable glands. They are made from UL-approved Nylon 66 and are IP 68 rated for protection in wet environments. These cord grips are designed to seal your enclosure from the environment and act as a strain relief.
These cord grips can be ordered with Metric, NPT, or PG threads. They are sized to work for cables from 3mm to 44 mm or .125" to 1.73". The standard color is Black. Other colors can be specially ordered.