This is EAI's own label fixed wheel multi tool. It is made by Makino of Japan and intended as a friend to the velodrome mechanic. Apparently forged out of solid stainless steel it might be a bit too heavy to take with you everyday unless you really do swap cogs every minute, or live in a particularly bad neighbourhood, but as a home tool it will last you a lifetime. The end that looks at first glance like a lockring tool includes a channel with a tooth that engages with your cogs and is most effective used on 13 - 16 tooth cogs. On the other end is a 15 mm box wrench on either side and 10 mm for adjusting chain tensioners on the end.