HK N-S Adjustable Gas Block Handguard Window Machining$14900 Category: Build Your Own Product ID: 8761 This is the machining service to create the gas block access window for side adjustment gas blocks. Service only, no parts included. HK N-S Adjustable Gas Block Handguard Window Machining quantity Add to cart Description Additional information Description This is the machining service to create the gas block access window for side adjustment gas blocks. Service only, no parts included. Additional information Weight 38 oz Dimensions 15 × 4 × 8 in