part no. ghg-1538 High quality rubber bushings. The 3/8" OD hose fits these sockets very snugly. Use a 1/2" hole size if it's not waterproof. I can use a 64 step drill to make it more waterproof. I will putting them on the bottom of DWC buckets that hold 3 gallons. Let me know whether they like it or not. I'm just tired of lugging full buckets of nutrient solution out of the greenhouse to throw away, and the tomato roots along with it free, so I hope I can fix this problem.