Manufacturer or distributor other than JR Products is SouthCo or RV Designer Collection H317. The JR # is 70445 for the large strike, and 70465 for the break-prone light duty. Supposedly they have a lifetime warranty, though I've not tried to run a claim with JR Products. I could send them all my broken strikes, but they'd just replace them with identical light duty ones.
Last summer the prices for a 70445 were $5.08 at Tweetys.com, and $3.32 at Easternmarine.com. $5.22 now at Amazon, but they then add $6.17 shipping - an Amazon Prime account might mitigate that asinine shipping; the thing weighs diddly but they rate it at 2 pounds, go figger. That's a good part of the problem, no matter where you buy, shipping adds insult. At one point I saw $1.99 at NW RV Supply in Eugene, but their online catalogue was ambiguous in such a way I could not confirm enough to order, and should have just called them.
Easternmarine.com, eg. Trailer Parts Superstore, can give you 10 large strikes for less than $52 total cost, shipping to the west coast, probably less if you live nearer to Delaware.
Generally, in order to make the fixes that were immediately needed last summer, it was cheaper and quicker in the long run to just go to the nearest Camping World. But it would be nice to get a more reasonable per each price somewhere, like maybe $1-3.
Joel