The Geissele Ultra Duty Lower Parts Kit (brand part no. 05-435B) is built for the most demanding operators, packing an ambidextrous safety and an oversized bolt release/catch alongside the rest of the internal parts needed to complete or rebuild an AR-15 lower receiver. Geissele machines this top-tier kit at its own facility in North Wales, Pennsylvania, using proprietary designs rather than off-the-shelf mil-spec parts, which is exactly why the brand has become a standard among professional end users and serious competitive shooters. Finished in black, it’s a premium, single-source option for anyone who wants their lower’s internals to match the standard set by a top-tier upper.

Key Specifications

• Includes an ambidextrous safety selector.
• Includes an oversized bolt release/catch.
• Built with proprietary Geissele designs, not generic mil-spec parts.
• Machined at Geissele’s own facility in North Wales, Pennsylvania.
• Finished in black.
• Package length of approximately 4.3 inches.

Frequently Asked Questions

Does this kit include an ambidextrous safety? Yes, along with an oversized bolt release/catch.

Where is this kit made? At Geissele’s own facility in North Wales, Pennsylvania.

Buy the Geissele Ultra Duty AR-15 Lower Parts Kit

Upgrade to a top-tier build with parts from Geissele Automatics. Order it from our Lubbock, Texas gun shop for fast, insured shipping, and see our full AR lower parts selection.