Clogs in the BW pipeline are hard to locate so onbord teams drill the pipeline in this search and cover the holewith duct tape or sheets of rubber. This leads to chemicals in water damaging the rubber or duct tape causing vacuum leaks that are impossible to locate, if you do not keep track of where the holes are and how many you have. We suggest using our rubber plug that is pushed inside the predrilled hole as serves as an inspection point resistant to chemicals and vacuum leaks. Rubber vacuum check point bottom is inserted through a predrilled 11mm hole. By opening the top white cap, you can easily check if that area is under vacuum or not. 11mm hole should be perfectly round to avoid vacuum leaks, so we suggest using our drilling tool which ensures perfectly drilled holes without leaks.