I HAVE A TLS350 AND WITH a polerstretch300 undergarment i need 38# for the suit alone in fresh water. That garment for me is probably good to high 40's in water temp. To go into salt water you will need even more weight. Probably 12#. I also have a polarstretch 100 and it needs 23# so the undies make a big difference. If you dont k now the tls is a shell suit and not a neopreme.