This keys were given as part of promotion of new steam level up bot: https://steamcommunity.com/id/levelstf

We have great rates 16 sets per 1 cs:go key (1600 experience), over 9000 game sets, and over 1400 happy customers.

Also we buy your cards :) https://steamcommunity.com/id/levelstfrandom
feel free to join our group and visit our site: http://levels.tf