This is the Scubapro Sport Steamer 0.5mm Men's Ultra-thin Profile Suit 

Features:

• Ideal for pool training, as a warm-water wetsuit, or as a base layer for thicker wetsuits.
• Nylon 2 Sides lining is soft, stretchy and extremely comfortable.
• Vertical YKK rear zipper with brass slider offers long-term durability and ease of use
• Foot straps prevent ride-up when used as a base layer.
• Flat-lock seam construction is comfortable against bare skin.
• Printed kneepads protect lower legs while maintaining softness.
• Made with X-Foam neoprene, a very specific limestone-based neoprene complying with strict PAH and REACH regulations.

This versatile ultra-thin neoprene steamer can be used for thermal protection while pool training, as a warm-water wetsuit, or as a base layer beneath a thicker wetsuit for cold-water diving. Made from extremely soft 0.5mm neoprene with a stretchy Nylon 2 Sides lining, this lightweight steamer comes with a vertical YKK zipper with brass slider for easy donning and doffing, and foot straps to prevent ride-up when used as a base layer. Printed kneepads increase durability while maintaining comfortable flexibility in the leg areas.