Gardena hose extension adapter, can be plugged into standard couplings, also no name.
O-ring made of TPU printable or at Amazon and co.: O-ring 16x11x2.5.
Printed in ABS with 0.2 layer height, 5/5 layers, 3 walls and 40% infill, support don't needed.
The author marked this model as their own original creation.