Looking for chains at ebay, I see, that they have 106, 114, 116 links and so on. 

I have a racing bike (2x7) and see, that chains are often announced as 6-7-8-speed, 10-speed, 11-speed. Since there are some prime numbers, I guess it is only back gear, which is taken into account? 

I found one picture with a printing on the containment: "6-7-8 speed" and "116 Links". So am I right - would this thing be alright for me, or do I have to take more information into account? 

Manufacture of the bike is Peugeot, of the mechanics: Shimano exage, an 80ies bike, and the chain lost attachment very abruptly after the cold winter. I'm not stick to Shimano, if I don't need to. Location Germany, if this is of importance.