My preference is Seekins, although I've used and liked cheaper versions of the same style. I like the infinite adjustment (as opposed to finite clicks) and the set and forget locking style. Note that they can still be adjusted with the locking screw tightened down, it just takes more torque and isn't likely to loosen if you don't adjust it back and forth a bunch.

Others may suggest click-adjustable gas blocks like Syrac etc, which might be your preference if you plan to tinker with the adjustment a lot.

Last edited by Yondering; 03/18/18.