Seriously, he's really tall.
Arsenal have just confirmed the signing of German international and former Werder Bremen captain Per Mertesacker, pending the completion of the registration process. Mertesacker fills a hole that fans have been clamoring to have filled for some time now, the tall, experienced central defender. As Aidan said last night there are concerns about Mertesacker's pace (particularly with Arsene Wenger's traditionally high defensive line), but he can make up for it with a very good positional sense.
Mertesacker is also well-known for his clean tackling style, with only 6 bookings in his Bundesliga career - considering how many suspensions we've had so far this year, that's a bit of a nice change of pace. He played in the Champions League last year with Bremen, and featured regularly in Germany's third-place World Cup campaign last summer. He doesn't have Premier League experience, but he's fully blooded at the highest levels of the game.
This signing also fills two mostly irrelevant holes that I'm personally excited about: he's German, and he's taller than me. And he's got Arsenal DNA, so that's nice. I really like this signing, he's a proven player available for a fairly small price (Sky have him coming in for around ₤10 million) and he changes our defensive style a bit. A player who can make a tackle cleanly and efficiently is always welcome in my book, and his size will help deal with set pieces and the like.
Two holes in the team down, hopefully at least one more to go.