- + Very low price
- + Easier to put on than open-cell
- + More durable than open-cell, less prone to tearing
- + Adequate for warm-water recreational diving
- − Closed-cell is less warm than open-cell at same thickness
- − Stiffer than open-cell, restricts breathing and arm movement
- − Not appropriate for water below 22°C
- − Lower neoprene quality compared to Cressi or SEAC
Overview
The IST 3mm closed-cell suit is the right purchase for one use case: a beginner diving in warm tropical water (24-28°C) who wants the minimum viable wetsuit at the lowest possible price.
It works. It provides thermal protection in warm water, it's more durable than open-cell, and you don't need to lubricate it before putting it on. For a diver doing casual reef snorkeling/freediving in Thailand or the Caribbean, the IST does the job at a price that removes the financial barrier to trying the sport.
For any serious freediving training, and especially for water below 22°C, the open-cell alternatives from Cressi, SEAC, or Beuchat are appropriate. The closed-cell construction limits chest expansion and insulates less efficiently, both of which matter for training use.