The Prospex Street series was developed to combine appearance and substance: combining the enthusiasm of Seiko fans for watch design styles along with 5 decades of experience in creating diving watches. The retro `` tuna '' shape of the 1975 diver model has been channeled into a more compact yet reinforced watch, sturdy enough to dive 200 meters under the sea but stylish enough to be worn on the street. like a `` tuna '' - due to its larger diameter and bold shape like a box of tuna.The accordion silicone strap combines high durability and comfort - a strap design invented by Seiko in 1975 as a practical solution to the expansion and contraction of a diver's wrist at different depths.