When the temperature is low, the semi-drysuit is perfect to protect against the cold while diving.
The semi-dry models are made of a thicker neoprene than the classic wet suits.
In order to keep warm while diving, these models of neoprene divesuits have wetsuit sleeves on the wrists and ankles to prevent water circulation.
The zippers used are made semi-waterproof by the addition of neoprene or for some brands by the use of 100% waterproof zippers like those used with wet suits.
On the neoprene side, the gluing is often reinforced by adding glue slides to the seams to prevent the possible passage of water.