Kayaking Resource

I am looking for a personal gps unit for hiking and kayaking. I saw one not too long ago that works very very simply. You turn it on and mark your position when starting out and it tells you how to get back. That’s all it does. It is meant to be worn on a jacket zipper or a lanyard. Can someone tall me where to find it or suggest something else? Thanks in advance.

I am looking for a waterproof GPS unit for kayaking. I do mostly lazy river and lake kayaking. It would also be used for biking, hiking and some driving. Color would be nice as would mapping. I’d choose color over mapping but that’s just me. I don’t really want to spend more on map subscriptions than on the unit itself.