I bought mine at a show. I was going to just get the 6.5", but they talked me into the 2.5", 4.5", 6.5" set. Boy, I'm glad I got the set!! While it is true that you can use the 6.5" ruler to cut smaller units, it is so very convenient to have the smaller ones the exact size of your patch. I have a small turn table cutting mat and can really rapidly trim lots of HTS with the exact size ruler.
I have never seen these on sale anywhere. Darn!

I bought a couple of the smaller ones first, which were great, but then I got the 6.5 inch one. That seems to be the one I go to most often.

I have all sizes. I have the strip set one on order. I don't use them all the time but when I need one, it sure is handy to have.

I watched the Bloc Loc ruler and it looks pretty slick. I already have 3 other ways to make HST.

I have come to the fact that I will 90 percent of the time not make the triangle correctly. I have decided to always make them a little bit bigger and trim them to size. That cuts down on my frustration!

I have the 3 size set also - love them, but if I could only have one, I would get the biggest as it will do it all.

I boughta set of three HST's at a quilt show a few years ago I have no regrets spending the money I use them all the time.

Can they work well if you choose to press your seams open?

Can they still work well if you choose to press your seams open?

I won a set of Bloc Loc rulers from a blog giveaway. They are nice and I'm glad I have them when I need to trim HSTs. I haven't tried them with open seams as they need the seam bulk to butt against.