We have two different brands of adjustable gas blocks for sale here at Scorpius Tactical. We have SLR and the new Strike Industries gas blocks. The SLR is priced at $124.95 and the Strike Industries is priced at $99.95. If you're looking to fine tune your AR these are the two best options out there. Stop on in and check these two awesome products out! As always give us a call if you have any questions.