Identify type of switch
What you have is a four way switch and a three way switch. The three way is the one with the three wires, the four way is the one with four wires. Take note of the 'point' wire on the three way if you intend to replace it, you should find some marking on the back of the switch that indicates which leg that is. 

As said in comments, it's unusual to see those in the US, but they are common in Europe and Asia. Akari makes an almost identical line of 'slim and stackable' wiring devices, except slightly smaller, if you're looking for an approved / listed replacement.