Gain every advantage.As the fourth generation of Blueseventy's top-end triathlon wetsuit, this year's Thermal Helix Tri Wetsuit has an illustrious cast of relatives to live up to. Blending features we've seen before with a few subtle, but effective updates, the Thermal Helix continues to live up to its pedigree as a wetsuit ideal for competitive triathletes serious about swimming with the lead group. Though Blueseventy doesn't specify which race distances the Thermal Helix caters best to, the advantages it offers will exponentially increase as your race distance does, and its jersey lining suits it better to early-season racing and colder bodies of water.Showing its distinction as a top-of-the-line wetsuit, the Thermal Helix is constructed with a strategic blend of panels that work to make your body movements as smooth as possible as you glide through the water. The panels are joined with triple-glued, blind-stitched, and internally-taped seams at high stress areas. New for this year, the formerly blue shoulder and back panels were updated to premium Yamamoto 40-cell neoprene, and Blueseventy eliminated seaming along the area to enhance shoulder and arm mobility, which can be a main issue in less expensive wetsuits. On the chest and torso panels, Yamamoto Aerodome neoprene addresses overall buoyancy and body position in the water, raising your hips in the water so that you're able to maintain an efficient "downhill" body position. Along the sides of the torso, gender-specific 3mm panels help facilitate quick body rotation while you're in the water and create a smooth transition area between the shoulder and back leg areas.The VO2 chest panel is one of the Thermal Helix's defining features, and it's been slightly reworked for this year's version to include a better split chest construction. Unlike more entry-level suits that do little to accommodate the chest, the Thermal Helix's anatomical design works with the lungs, stretching as you breathe so that you feel less of a drastic difference during hard efforts compared with swimming sans wetsuit. Lining the top of the wetsuit, Blueseventy's orange zirconium jersey gives the Thermal Helix its cold-water distinction, helping reduce water absorption and insulate your core further against heat loss if you're swimming in tiring, bracingly cold water. The forearm panels employ honeycomb patterning to help you pull water more efficiently while a full neoprene catch panel at the wrists helps you retain warmth in a vulnerable area.Blueseventy found itself less than satisfied with last year's collar design, so this year, it reshaped the lower collar, complementing it with a curved closure flap that creates a slimmer, lower profile design less likely to get in your way while you swim. You'll glide through the water through repeated uses with the wetsuit's durable SCS coating, and the full-length YKK zipper works quickly and reliably when you're jogging in to T1.