A low pressure directional stop bypass device including a saddle fitting having an axially extending tubular connection element having a connection element wall forming a lateral bypass port, a valve assembly connected with the axially extending tubular connection element having a first valve port in fluid communication with the lateral bypass port and having a second valve port, and a stuffing box connected with the second valve port. A launch tube assembly is inserted through the stuffing box and the valve assembly into the axially extending tubular connection element. The launch tube element includes an outer tubular member, an inner tubular member disposed within the outer tubular member, and a stopper supply tube having a leading end and a trailing end and disposed within the inner tubular member. A flexible inflatable stopper plug connected with the leading end of the stopper supply tube. Connected with the outlet end of the outer tubular member is at least one guidance pin which ensures insertion of the flexible inflatable stopper plug into a pipe fitted with the saddle fitting in a predetermined direction.