I've been working on an idea for a locking strap to secure jerry, NATO and Sceptre cans. My goal was to come up with one strap that would work with all types of cans that would be locking and secure, and adjustable so the can could be snugged down tight enough to eliminate can movement or rattles. I also wanted the strap to be flexible to deal with the different can shapes, particularly the rounder shape of the Sceptre cans.
Today I made up a prototype, here are a few photos showing it with jerry and NATO cans. Unfortunately I don't have a Sceptre can here to try it with.
The tray hooks at the bottom ends of the strap swivel, so the strap can be used either to secure only the can (left photo), or it can be angled to also secure the cap (middle). NATO cans have caps on the ends of a spout so they can't easily be secured that way.
Adjustments are done by means of the adjustable latch (3/4" range), and the removeable-link chain (1.5" each link). The math works out to basically infinite adjustment - if the adjustment on the latch isn't enough, remove or add one or more links and start with the other end of the range of the latch adjustment.
The strap is all metal, so it's pretty secure. Here's a photo of the strap on the workbench; a few extra links are in the photo as well. BTW it takes one more link to go over the jerry can cap than it does to go through the handle.
One more refinement is to encase the link portion in a flexible plastic sleeve so the links don't scratch metal cans:
The retail cost of buying the materials to make this prototype was less than $10. This is a proof-of-concept prototype, so there are a few refinements I'd add, but it definitely meets the requirements I defined for it. I have no idea if this would make sense as a commercial product, I just designed and built this one because it was an interesting design challenge and I wanted straps like this for my own use.