The Premium Rubber collection is made from high-quality FKM rubber. Those straps are super flexible and you will definitely notice the difference to other rubber materials.  
 
The tropical pattern takes inspiration from the original SEIKO tropical rubber watch strap made during the 60's.
 
Length(s) : 130 / 80mm
Thickness : 3mm
Design : Tropical Pattern
Material : FKM Rubber
Width : 20mm or 22mm