Yes, the one pictured is a single-stroke function. The biggest diameter I've been able to find without the ratchet is 1-5/8". I've been using it for a couple of years and love it. It does take a bit of hand strength, so if you've got arthritis, carpal tunnel or other issues, it might not be the best choice. Yes, best to go to a hardware store to buy one in person and feel the function.
I love mine because it's error-free, no missed cuts, no danger of cutting myself, it's fast and about as humane a method as I could find. For some weird reason, I don't think I could do the broomstick method (ew!), and haven't been very accurate or efficient with an axe or hatchet. With these cutters, it's problem-free and over in an instant.