- Weep hole (drain pipe) for sand trap or concrete wall
- 2016-10-25 23:18
- Weep hole , drainage pipe withflap valve , can regulate the water between inside and outside of concrete channel.You don
- PVC flap valve (for sewage back flow)
- 2016-10-23 15:38
- Movement The flap gateusuallydischarge the waterby the pressure of drainage.When the water leveloutside flap gategets h