I had to contact them to order mine with their locking custom bit set. I have it around somewhere. Never used it as I ended up buying a bunch from Lee Valley as I got the impression from Burketek that there were not going to make more.
If you can’t find the original online maybe check out the Ti EDC Wrench at Kickstarter. Though I think it’s too much money.
Not sure about that Amazon knock off, I did consider it but decided I didn’t trust those folks to get the tolerances right.
Good luck my friend.