OK. It's old kit and not specifically for the bike (but should be OK behind the screen of my RT?) but it's cheap and I believe updated maps are available on memory cards or are they?
Takes current NT Mapping which can go on SD card, you'll need to register it with Garmin to update the mapping that which might be a stumbling block. Do you know it's history
It won't do routing in the sense that'll be useful for recreational biking though so only expect it to get from where you are to where you want to go by a route that it decides, that's the critical bit that would make it useless for me...