I need opinions!

Allison
My boyfriend and I have been talking about getting engaged for a long time, but recently started talking about it more concretely and making actual plans. I think I know when he's planning to propose, not because I was trying to guess but a few things he said just kind of gave me that feeling. 
For a while I've had this idea that I wanted to get him a gift as well when we get engaged so that it's less like he's asking me and more like we're deciding to do it together, but at the same time I didn't want to "steal his thunder" or something lol. I just thought it would be nice that he could have something to remember the moment like I would with the ring. 
I thought about getting him a ring too at first, and then thought about a nice watch, but he can't wear anything like that with the job he has and it would just sit there most of the time. I was looking into other gift ideas and came across this engravable, credit card sized bottle opener you can keep in your wallet. 
We both like beer and it's something small that he can keep on him all the time so thought it was kind of a cool idea but I'm still not sure. 
Do you guys think it's a cute idea, or does it seem stupid/tacky? Would it take away from the moment if I gave it to him when he gives me the ring? I have a few examples of what I would get engraved, I'd love opinions on which one you like best!