GARDENA coupling: Connecting portion for secure hose connection, connecting two tubes to extend, for the transition of 19 mm (3/4) - on 13 mm (1/2) hoses, packaged (2931-20) : Amazon.co.uk: Garden
Fast watering connection 19 mm (3/4") - GARDENA
HydroSure Triple Quick Click Hose Joiner | Water Irrigation
GARDENA Hose Joiner/Repairer 13mm | Joiner, Hose, True value hardware
The Complete Guide to Garden Hose Fittings - Dengarden