Standard water-resistant Transducer
Loctite 3090 is a very fast curing glue (2 minutes), use it in places that are difficult to reach or when you want to glue a transducer on a vertical surface or upside down.
Loctite 3295 allows you more time to position your transducer (5 minutes). This glue is also more resistant to chemicals and solvents. You need a glue gun for this glue.
TEC7 is a professional, water resistant sealant.