For the first time in 2012, Bloomsday will time finishers using B-tag timing by Chronotrack. When you check in on Bloomsday weekend, you'll find plastic strips on the back of your race number. These are B-tags. Unlike the D-tags used the past two years, the B-tags stay right there on the back of the number. Please don't remove them! 

 

Like the D-tag, the B-tag uses radio frequency identification to track each participant individually. But the B-tag can be read from the bib number, and doesn't need to be in the laces of the shoe. In the end, the result will be the same; every runner, jogger and walker will be timed precisely from the moment they cross the starting line to the moment they cross the finish.