Garmin 405 and Garmin 305 Forerunner are quite different models, although you may expect taht 405 is successor of 305, it is not fully same concept. Read the differences and get the right wrist gps for you:

http://garmin-305-review.com
http://garmin-305-review.com/garmin-305-vs-405/

Buy Garmin 305Forerunner at best price at Amazon:
http://www.amazon.com/Garmin-Forerunner-Receiver-Heart-Monitor/dp/B000CSWCQA/ref=as_li_tf_ssw?&linkCode=wss&tag=mirjamitropho-20

Buy Garmin 405 Forerunner:
http://www.amazon.com/Garmin-Forerunner-Wireless-GPS-Enabled-Monitor/dp/B0011UNMIK/ref=as_li_tf_ssw?&linkCode=wss&tag=mirjamitropho-20