What we have here is a wonderful Mid-Century Czechoslovakian side chair designed by Miroslav Navratil for Vertex in the 1960s. The seat itself is made from fibreglass and envelopes your body when you sit in it (soooo comfortable) and is covered in the original brown fabric. The legs are made from beech and are very sturdy and built to last like all communist era furniture was.
 
The dimensions are:
 
Height: 800mm Seat Base: 440mm
Width: 570mm
Depth: 610mm