Need a screw-on taillight

[rocksalt27]

So I've got a box mounted on my rear rack and I want a taillight that I can screw or bolt vertically on the back of it. I would really prefer a battery powered LED. I talked to a salesman and it he said that everyone is going to the strap-on type lights. Let's just say I'm not into strap-ons.

Any advice would be greatly appreciated.

 

[allen standley]

I also have no use for the "strap ons or the wrap arounds'. I always end up home making a mount vertical as you describe. Here's a good one I use which allows for an easy do it yourself job.
https://www.amazon.com/Rechargeable...65555410&sr=8-22&keywords=tail+lights+bicycle