If you have a desk job it is vital that you employ a good sitting posture and invest in an ergonomic chair. The other more affordable (and definitely more portable) option is the BackJoy SitSmart Relief seat.
Developed by BackJoy, a US company, the SitSmart is shaped such that it activates your core muscles, supports your gluteus and frees up the tailbone. SitSmart tilts your hips upwards so that your spine moves into a comfortable “floating” position over the seat and achieves the natural “S” shape instead of being kept in hunched position.
The two main models for the SitSmart series are the SitSmart Relief and the SitSmart Posture Plus. The main difference between these two models is that the Posture Plus has a waterproof EVA foam and so is more preferable if you want to take it outdoors. The SitSmart Relief on the other hand has a soft fabric covering and is filled with a layer of pressure-relieving foam padding for extra comfort.