SIS-USA manual, crank and electric height adjustable workstations and ergonomic accessories improve comfort and productivity in office, call center, healthcare, training, and higher education environments. We design workstations offering seated range or sit-to-stand flexibility in nearly any shape and size. SIS-USA offers several upgrades that ensure future flexibility, allowing workstations to adapt as technology and other needs change. SIS-USA offers a lifetime warranty on office furniture.