Refill Grit Kit w MJR Tumblers 12,000 Grit Extreme Polish - Premium

In this review the Refill Grit Kit with MJR Tumblers' exclusive 12,000 grit sub micron aluminum oxide polish is assessed for hobbyists and small-scale lapidary users seeking an exceptional final shine. The bottom line: this refill kit is aimed at those who already use 40lb rotary or vibratory tumblers and want a professional-level finish with minimal measuring hassle. The standout reason to buy is the included 12,000 grit Extreme Aluminum Oxide Polish, which delivers a noticeably higher shine compared with standard polishing compounds.

Key Features

• 12,000 Grit Extreme Polish: Provides a sub micron aluminum oxide finish that produces a deep, mirror-like polish on stones and crystals.
• Premeasured Stages: All four stages come premeasured for a 40lb tumbler so users can pour and run without calculations or weighing.
• Complete 4-Stage Kit: Includes coarse 60/90, fine 120/220, pre-polish 400/600, and extreme 12,000 grit to cover the full tumbling process.
• Works with Rotary and Vibratory Tumblers: The formulas are compatible with common tumbler types, offering flexibility for different setups.
• Clear Instructions: Each purchase includes step-by-step polishing instructions with tips and tricks to improve results and reduce common mistakes.

Who It's For

This kit is best for hobbyists, rock collectors, and small workshop users who already own a 40lb capacity tumbler and want a premium finish without measuring grits themselves. The premeasured stages save time and reduce setup errors, making it suitable for users who prefer a straightforward, repeatable process.

It is less appropriate for someone who never tumbles before or who uses much smaller or much larger barrels without adjusting portions. Buyers on a tight budget who prioritize minimal cost over top-tier shine may want to compare quantity versus price before committing.

Pros & Cons

Pros

• Premeasured four-stage system reduces setup time and simplifies the tumbling process.
• 12,000 grit sub micron aluminum oxide polish produces superior shine and improved surface clarity.
• Good set of grit sizes included so the kit handles everything from shaping to final polish.

Cons

• Some customers mention labeling and perceived value concerns, so quantity and cost should be evaluated against other options.

Specifications

Brand	MJR Tumblers
Kit Size	40 lb kit (premeasured for 40lb tumbler)
Coarse Grit	40 oz 60/90 silicon carbide
Fine Grit	40 oz 120/220 silicon carbide
Pre-polish	20 oz 400/600 silicon carbide
Extreme Polish	20 oz 12,000 grit sub micron aluminum oxide
Company	Disabled and veteran owned, Pecatonica, IL, USA

Our Verdict

The Refill Grit Kit with MJR Tumblers' 12,000 grit Extreme Aluminum Oxide Polish is a strong choice for anyone wanting a premium polish without the hassle of measuring. It is particularly valuable for 40lb tumbler owners who want consistent, high-quality results and clear instructions; however, buyers should weigh the kit's quantity and price against alternatives if cost is the main concern.

Frequently Asked Questions

Will this kit work in my vibratory tumbler?
Yes, the kit is premeasured to work with both rotary and vibratory tumblers designed for a 40lb charge.

Does the 12,000 grit really make a difference?
Users report a noticeably deeper shine and improved surface clarity compared with common lower grit polishes, thanks to the sub micron aluminum oxide.

Is this kit ready to use out of the box?
Yes, all four stages are premeasured and include instructions, so you can pour the grits into the tumbler and begin the recommended cycle.