Henco plastic press fittings: the best solution, including for surface-mounted installations.
18PKW White straight connectors with female thread (CW617): 

Solutions
Building installations
Industry
Utility
Shipbuilding
Applications
Potable water
Heating
Cooling
Compressed air
Sanitary
| Article number | Diameter | Length | Colours | ||
|---|---|---|---|---|---|
18PKW-1604  | 16x1/2"  | 59.5mm  | White  | Specifications | |
18PKW-2004  | 20x1/2"  | 59mm  | White  | Specifications | |
18PKW-2005  | 20x3/4"  | 62.5mm  | White  | Specifications | |
18PKW-2605  | 26x3/4"  | 62.5mm  | White  | Specifications | |
18PKW-2606  | 26x1"  | 70mm  | White  | Specifications | |
18PKW-3206  | 32x1"  | 81mm  | White  | Specifications | |
18PKW-3207  | 32x5/4"  | 89.5mm  | White  | Specifications | |