The Seek Amp 5/4 Back Zip stands for an epic stretch without compromising warmth, making it the perfect wetsuit all year round. Freedom of movement in arms and shoulders is key, no matter if you paddle or hold on to your kite or sail. To improve flexibility in this crucial area, ION uses a new rhombus-shaped outside lining. It stretches easily, thanks to the unique structure. Additionally, recycled Eco_Stretch lining at the torso and legs maintains comfy stretch throughout the entire suit (black colorway only). The secret for optimal heat retention lies in ION's super flexible Hot_Stuff 2.0 thermo lining combined with toasty warm Plasma_Plush 2.0. On top, I_foam neoprene traps more air due to its foamy structure, improving heat retention and flexibility. Seek Amp Backzip models feature additional protection pads at the shins.