Yeah, this is going to be a dumb response... but seriously, you might want to try a plain chain. You can find nice looking ones at a jewelry store, sometimes a department store. They look 100% vanilla, yet are plain and, if you find the right one, will represent your submissiveness perfectly... The last thing you want to do is put your vanilla job in jeopardy, so I would error on the side of caution & not wear ANYTHING that could be construed as "kinky"--at least, if you are working in a professional setting. In other words, the eternity collars, while nice, are not really workplace-saavy (have one, tried it). Neither are 99.99999% of the collars sold on BDSM sites.

Sometimes, simpler is better.

Good luck, hope you find what you are looking for!