well, i had an idea to secure this pro tuff bin using 4 short ratchet straps, one in each corner to secure it to the trailer. i'll buy 4 matching master locks. i will drill a hole in the ratcheting handle and frame of the straps and run the padlock thru the hole so they can't be opened.

after i set it on there i realised there is no way to attach ratchet straps to the bin so the idea may not work.

i know if someone wants the box they'd just cut the straps. its not intended to be high security. i'm not going to haul it to the grocery store and leave it outside while i go shopping. it's intended for situations where i'll remain within sight distance of the bike.