You can find the Faxon Low-Profile 3 Screw .625" Gas Block here.

The Faxon Low-Profile Gas Block has an ultra-low profile, making it perfect for use with any handguard system. Made from high-strength steel, all Faxon gas blocks have a matching black luster to Faxon barrels. The lightweight design is drilled through the middle of the profile. The gas block clamps onto the barrel using 3 Allen keys on the bottom of the block. These ultra-low profile gas blocks are perfect for any rail system.

Features:

• .625" Gas journal compatibility
• Weight: .07 Lbs
• Width: 1.00"
• Height: ~1 & 7/32"
• 3 set screw mounting for added security