--- product_id: 767855153 title: "400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit" brand: "mjr tumblers" price: "$352.18" currency: USD in_stock: true reviews_count: 3 category: "Mjr Tumblers" url: https://www.desertcart.us/products/767855153-400-600-grit-20lb-aluminum-oxide-rock-tumbler-pre-polish store_origin: US region: United States of America --- # Rotary & vibratory compatible 400/600 grit precision USA veteran-owned quality 400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit **Brand:** mjr tumblers **Price:** $352.18 **Availability:** ✅ In Stock ## Summary > ✨ Elevate your rock tumbling game with pro-grade grit ⚙️ ## Quick Answers - **What is this?** 400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit by mjr tumblers - **How much does it cost?** $352.18 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/767855153-400-600-grit-20lb-aluminum-oxide-rock-tumbler-pre-polish) ## Best For - mjr tumblers enthusiasts ## Why This Product - Trusted mjr tumblers brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Multi-Material Mastery:** Perfect for stones, minerals, and glass polishing projects - • **Premium Aluminum Oxide:** Consistent abrasion ensures uniform stone refinement every time - • **Versatile Compatibility:** Works seamlessly with both rotary and vibratory tumblers - • **Flawless Pre-Polish Finish:** Stage 3 grit smooths scratches for a mirror-ready surface - • **Trusted Veteran-Owned Brand:** Support quality and service from a USA-based, veteran-owned company ## Overview MJR Tumblers’ 400/600 grit aluminum oxide pre-polish is a premium lapidary grit designed for stage 3 rock tumbling. Compatible with rotary and vibratory tumblers, it delivers consistent, fine abrasion to smooth and prepare stones, minerals, and glass for final polishing. Proudly made by a USA veteran-owned brand, this grit ensures reliable, professional results for hobbyists and pros alike. ## Description Product description Review: Great Product Line and Attention to Detail - I recently placed an order for 4lbs of step 3 pre-polish aluminum oxide from MJR Tumblers, and was pleasantly surprised that each lb was separated into 4 heavy duty ziplock bags. This allows me to store just wants needed in my storage ben, while keeping my extra product in the semi air tight bag which it was shipped in. I was also impressed with there product line, I struggled to find 400 to 600 grit in the aluminum oxide on desertcart, but I am happy MJR Tumblers turned out to be the only one I could find, because i plan on making more orders with this company😊 they also sent some great literature along with my order, including knowledge of there FB page I can join and share my passion with other Rock Hounders🥰 Thank you for this service AND a Special Thanks for your Service 🫡100% satisfied customer!!! Review: Exactly as described - Is exactly what it claims and works great at a reasonable cost. ## Features - STAGE 3 PRE-POLISH FOR SMOOTH TRANSITION: This 400/600 grit aluminum oxide is designed for the third stage of rock tumbling, refining stone surfaces after initial shaping and smoothing. Helps prepare rocks for final polishing by reducing visible scratches and improving surface consistency. - PREMIUM ALUMINUM OXIDE FOR CONSISTENT RESULTS: Made from high-quality aluminum oxide, this grit provides reliable performance during the pre-polish stage. Designed to deliver even abrasion across stones, helping achieve a smooth and uniform finish before final polishing. - COMPATIBLE WITH ROTARY & VIBRATORY TUMBLERS: Suitable for use with most rock tumblers, including rotary and vibratory machines. A versatile option for maintaining your rock polishing process or replacing stage 3 grit in your workflow. - IDEAL FOR ROCKS, GLASS & LAPIDARY USE: Can be used for polishing stones, minerals, and even glass materials. Provides flexibility for a range of polishing applications, making it a useful addition to any rock tumbling setup. - USA OWNED BRAND WITH TRUSTED QUALITY: Offered by a USA-based, disabled and veteran-owned company. MJR Tumblers provides dependable rock tumbling supplies designed for consistent performance and ease of use. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0CP8VPZXZ | | Best Sellers Rank | #25,154 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #38 in Tumbling Media | | Brand | MJR Tumblers | | Brand Name | MJR Tumblers | | Compatible Material | Premium Quality Aluminum Oxide | | Customer Reviews | 4.3 out of 5 stars 17 Reviews | | Grit Material | Premium Quality Aluminum Oxide | | Grit Material Type | Premium Quality Aluminum Oxide | | Grit Number | 600 | | Grit Type | Super Fine | | Included Components | Instructions and Grit | | Manufacturer | MJR Tumblers | | Material | Premium Quality Aluminum Oxide | | Material Type | Premium Quality Aluminum Oxide | | Number of Items | 1 | | Part Number | MJR20p400/600AO | | Unit Count | 1.0 Count | ## Product Details - **Brand:** MJR Tumblers - **Grit Material:** Premium Quality Aluminum Oxide - **Grit Number:** 600 - **Grit Type:** Super Fine - **Material:** Premium Quality Aluminum Oxide ## Images ![400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit - Image 1](https://m.media-amazon.com/images/I/51FmTcNLZ0L.jpg) ![400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit - Image 2](https://m.media-amazon.com/images/I/71VEE0eqiZL.jpg) ![400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit - Image 3](https://m.media-amazon.com/images/I/71d6xQMgukL.jpg) ![400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit - Image 4](https://m.media-amazon.com/images/I/61UV0iJ0o5L.jpg) ![400/600 Grit 20lb Aluminum Oxide Rock Tumbler Pre Polish, Stage 3 Rock Polishing Grit for Stone Polishing, Compatible with Rotary & Vibratory Tumblers, Premium Lapidary Grit - Image 5](https://m.media-amazon.com/images/I/71cJ5kYQK2L.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Great Product Line and Attention to Detail *by J***K on March 13, 2026* I recently placed an order for 4lbs of step 3 pre-polish aluminum oxide from MJR Tumblers, and was pleasantly surprised that each lb was separated into 4 heavy duty ziplock bags. This allows me to store just wants needed in my storage ben, while keeping my extra product in the semi air tight bag which it was shipped in. I was also impressed with there product line, I struggled to find 400 to 600 grit in the aluminum oxide on Amazon, but I am happy MJR Tumblers turned out to be the only one I could find, because i plan on making more orders with this company😊 they also sent some great literature along with my order, including knowledge of there FB page I can join and share my passion with other Rock Hounders🥰 Thank you for this service AND a Special Thanks for your Service 🫡100% satisfied customer!!! ### ⭐⭐⭐⭐⭐ Exactly as described *by Z***A on May 14, 2026* Is exactly what it claims and works great at a reasonable cost. ### ⭐⭐⭐⭐⭐ True Grit *by B***. on April 6, 2026* Good stuff and value with Prime shipping --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.us/products/767855153-400-600-grit-20lb-aluminum-oxide-rock-tumbler-pre-polish](https://www.desertcart.us/products/767855153-400-600-grit-20lb-aluminum-oxide-rock-tumbler-pre-polish) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-07-23*