STRi. DA SX Folding Bike. With a truly unique triangular frame design, 3 tubes instead of traditional construction of a bike frame, it can be opened & folded in a few seconds without any tools, the greasless drive belt replaced the oily chain. Simple and Clean! That is the STRi. DA advantage. The STRi. DA SX folding bike features the first completely new bicycle geometry in 95 years... Supplies are limited. Check merchant site for complete details and availability.