We have the new JP/Syrac Ordinance Adjustable Gas blocks. These are low profile so they fit under just about any free float rail or handguard. They are adjustable for gas flow from fully open to completely shut off. There are 16 settings so you can get the perfect gas setting for the smoothest, softest shooting possible. The best part is that the settings lock into place with a spring loaded detent so it won’t change unless you want. And you can change the settings from the front while it is under a handguard, so you can do it in the field or on the range. These are very well made and are the gas blocks many shooters that shooters have wanted.