1STec 20m Underground Cable Conduit Ducting Hose Pipe Channel for TV Coax, Electric Wire, Garden Lights, Fish Pond Low Voltage Pumps, Power Socket Lead Burial (20 Metre, 20mm External 14mm Internal) :
The Definitive Guide to Underground Cable Ducting - E-Tech Components
Everything you should know about underground ducting - Drainage Superstore Help & Advice