Small rail side toolbox?

I'm looking for a small toolbox that can fit under the factory tonnaeu cover and just behind the wheel well. Is there anything out there that attaches to the side rails and isn't too big?

I'm thinking of getting a small portable toolbox and rigging some rail cleats to stabilize it. The rail doesn't necessarily need to hold all the weight, just stabilize the box. I'd prefer something more narrow and tall.

Any suggestions?

 

This. https://www.4wheelparts.com/p/truxedo-saddle-bag-1705213/_/R-BKHI-1705213?gclid=EAIaIQobChMIv6GV-M3q4AIVSR-tBh2l_wFrEAQYCyABEgI_VvD_BwE&ecmp=s:google_738958544_34063253890__aud-255917446700la-326080807384_TruXedo_TRX1705213_base_US&utm_source=google&utm_medium=cpc&utm_campaign=shopping&emlprox=out&ppcfon=1&gp=1&utm_source=google&utm_medium=cpc&sc_intid=TRX1705213&ef_id=EAIaIQobChMIv6GV-M3q4AIVSR-tBh2l_wFrEAQYCyABEgI_VvD_BwE:G:s&s_kwcid=AL!7836!3!172996091001!!!g!326080807384!&utm_source=google&utm_medium=cpc&utm_campaign=SC Shopping - NTM Mobile&ecmp=s:google_738958544_34063253890__aud-255917446700l

Or an ammo can